Class 7, Maths, Chapter 4, Exercise 4.3 Solutions
Q.1. Solve the following equations:
(a) $\mathrm{2y+}\frac{\mathrm{5}}{\mathrm{2}}\mathrm{=}\frac{\mathrm{37}}{\mathrm{2}}$
(b) 5t + 28 = 10
(c) $\frac{a}{5}\mathrm{+3=2}$
(d) $\frac{\mathrm{q}}{\mathrm{4}}\mathrm{+7=5}$
(e) $\frac{\mathrm{5}}{\mathrm{2}}\mathrm{x=-5}$
(f) $\frac{\mathrm{5}}{\mathrm{2}}\mathrm{x=}\frac{\mathrm{25}}{\mathrm{4}}$
(g) $\mathrm{7m+}\frac{\mathrm{19}}{\mathrm{2}}\mathrm{=13}$
(h) 6z+10=-2
(i) $\frac{\mathrm{3l}}{\mathrm{2}}\mathrm{=}\frac{\mathrm{2}}{\mathrm{3}}$
(j) $\frac{\mathrm{2b}}{\mathrm{3}}\mathrm{-5=3}$
Q.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
Q.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)
Q.4. (a) Construct 3 equations starting with x = 2
(b) Construct 3 equations starting with x = – 2
Ans:
(a) Construct 3 equations starting with x = 2
(i) Adding both sides 2, we get
⟹ x+2=2+2
⟹ x+2=4
(ii) subtracting both sides by 2, we get
⟹ x-2=2-2
⟹ x-2=0
(iii) Multiplying both sides by 2, we get
⟹ x×2=2×2
⟹ 2x=4
(b) Construct 3 equations starting with x = – 2
(i) subtracting both sides 3, we get
⟹ x-3=-2-3
⟹ x-3=-5
(ii) Multiplying both sides by 2, we get
⟹ x×2=-2×2
⟹ 2x=-4
(iii) Multiplying both sides by 3, we get
⟹ x×3=-2×3
⟹ 3x=-6