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Exercise 4.3 - Chapter 4 Simple Equations class 7 ncert solutions Maths - SaraNextGen [2024]


Question 1:

Solve the following equations.

(a) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m59a85ed9.gif  (b) 5t + 28 = 10 (c) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m622aaebc.gif

(d) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m62d9170c.gif  (e) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m253ceb79.gif  (f) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_4c52b6b0.gif

(g) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m7a57cbfb.gif  (h) 6z + 10 = − 2 (i) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m1ccd822b.gif

(j) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m2ad9fd5.gif

Answer:

(a) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m53d15103.gif

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_628a024c.gif  (Transposing https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_21c6157c.gif to R.H.S.)

Dividing both sides by 2,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m845d9af.gif

(b) 5+ 28 = 10

5t = 10 − 28 = −18 (Transposing 28 to R.H.S.)

Dividing both sides by 5,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m7e730d8b.gif

(c) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m4f3a1226.gif

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m2be87a74.gif  (Transposing 3 to R.H.S.)

Multiplying both sides by 5,

a = −1 × 5 = −5

(d) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m44940f90.gif

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m49a0450b.gif  (Transposing 7 to R.H.S.)

Multiplying both sides by 4,

q = −8

(e) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_ma1975c9.gif

Multiplying both sides by 2,

5= −10 × 2 = −20

Dividing both sides by 5,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_446b3c06.gif

(f) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m15f9110.gif

Multiplying both sides by 2,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_mb0f06ff.gif

Dividing both sides by 5,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m7f90faef.gif

(g) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m49e02b2e.gif

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_66e35ef7.gif  (Transposing https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m68c2bc8.gif  to R.H.S.)

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_64b69fa6.gif

Dividing both sides by 7,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m229b1d06.gif

(h) 6z + 10 = −2

6z = − 2 − 10 = −12 (Transposing 10 to R.H.S.)

Dividing both sides by 6,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_a5eadb2.gif

(i) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m193c92de.gif

Multiplying both sides by 2,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_7105df.gif

Dividing both sides by 3,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_48c9b700.gif

(j) https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m2ad9fd5.gif

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_m8e1ac8d.gif  (Transposing −5 to R.H.S.)

Multiplying both sides by 3,

2b = 8 × 3 = 24

Dividing both sides by 2,

b = https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1886/Chapter%204_html_2e3f287f.gif = 12

Question 2:

Solve the following equations.

(a) 2 (x + 4) = 12 (b) 3 (n − 5) = 21

(c) 3 (n − 5) = − 21 (d) −4 (2 + x) = 8

(e) 4(2 − x) = 8

Answer:

(a) 2 (x + 4) = 12

Dividing both sides by 2,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1887/Chapter%204_html_m11aa47bf.gif

x = 6 − 4 = 2 (Transposing 4 to R.H.S.)

(b) 3 (n − 5) = 21

Dividing both sides by 3,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1887/Chapter%204_html_1c314e87.gif

n = 7 + 5 = 12 (Transposing −5 to R.H.S.)

(c) 3 (n − 5) = −21

Dividing both sides by 3,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1887/Chapter%204_html_72fbee65.gif

n = − 7 + 5 = −2 (Transposing −5 to R.H.S.)

(d) −4 (2 + x) = 8

Dividing both sides by −4,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1887/Chapter%204_html_3223d90a.gif

x = − 2 − 2 = −4 (Transposing 2 to R.H.S.)

(e) 4 (2 − x) = 8

Dividing both sides by 4,

2 − x = 2

x = 2 − 2 (Transposing 2 to R.H.S.)

x = 0

x = 0

Question 3:

Solve the following equations.

(a) 4 = 5 (p − 2) (b) − 4 = 5 (p − 2)

(c) 16 = 4 + 3 (t + 2) (d) 4 + 5 (p − 1) = 34

(e) 0 = 16 + 4 (m − 6)

Answer:

(a) 4 = 5 (p − 2)

Dividing both sides by 5,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1890/Chapter%204_html_68063209.gif

(b) − 4 = 5 (p − 2)

Dividing both sides by 5,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1890/Chapter%204_html_m311afaa7.gif

(c) 16 = 4 + 3 (t + 2)

16 − 4 = 3 (t + 2) (Transposing 4 to L.H.S.)

12 = 3 (t + 2)

Dividing both sides by 3,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1890/Chapter%204_html_m34784cfb.gif

4 = t + 2

4 − 2 = t (Transposing 2 to L.H.S.)

2 = t

(d) 4 + 5 (p − 1) = 34

5 (p − 1) = 34 − 4 = 30 (Transposing 4 to R.H.S.)

Dividing both sides by 5,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1890/Chapter%204_html_m82563e2.gif

p = 6 + 1 = 7 (Transposing −1 to R.H.S.)

(e) 0 = 16 + 4 (m − 6)

0 = 16 + 4m − 24

0 = −8 + 4m

4m = 8 (Transposing −8 to L.H.S)

Dividing both sides by 4,

m = 2

Question 4:

(a) Construct 3 equations starting with x = 2

(b) Construct 3 equations starting with x = − 2

Answer:

(a) x = 2

Multiplying both sides by 5,

5x = 10 (i)

Subtracting 3 from both sides,

5x − 3 = 10 − 3

x − 3 = 7 (ii)

Dividing both sides by 2,

https://img-nm.mnimgs.com/img/study_content/curr/1/7/3/34/1893/Exercise%204.3%20PAGe%2089_html_3386d533.gif

(b) = −2

Subtracting 2 from both sides,

x − 2 = − 2 − 2

x − 2 = −4 (i)

Again, = −2

Multiplying by 6,

6 × x = −2 × 6

6x = −12

Subtracting 12 from both sides,

6x − 12 = − 12 − 12

6x − 12 = −24 (ii)

Adding 24 to both sides,

6x − 12 + 24 = − 24 + 24

6x + 12 = 0 (iii)

Also Read : Exercise-4.4-Chapter-4-Simple-Equations-class-7-ncert-solutions-Maths

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