## Maharashtra Board Class 9 Maths Solutions Chapter 4 Ratio and Proportion Practice Set 4.3

Question 1.

If \(\frac { a }{ b }\) = \(\frac { 7 }{ 3 }\), then find the aIues of the following ratios.

Solution:

Question 2.

If \(\frac{15 a^{2}+4 b^{2}}{15 a^{2}-4 b^{2}}=\frac{47}{7}\), then find the value of the following ratios.

Solution:

Question 3.

If \(\frac{3 a+7 b}{3 a-7 b}=\frac{4}{3}\)then find the value of the ratio \(\frac{3 a^{2}-7 b^{2}}{3 a^{2}+7 b^{2}}\).

Solution:

Question 4.

Solve the following equations.

Solution:

This equation is true for x = 0

∴ x = 0 is one of the solutions.

If x ≠ 0, then x^{2} ≠ 0

∴ \(\frac { 1 }{ 12x – 20 }\) = \(\frac { 1 }{ 8x + 12 }\) … [Dividing both sides by x^{2}]

∴ 8x + 12 = 12x – 20

∴ 12 + 20 = 12x – 8x

∴ 32 = 4x

∴ x = 8

∴ x = 0 or x = 8 are the solutions of the given equation.

∴ 21(x – 5) = 4(2x + 3)

∴ 21x – 105 = 8x + 12

∴ 21x – 8x = 12 + 105

∴ 13x = 117

∴ x = 9

∴ x = 9 ¡s the solution of the given equation.

∴ 9(4x + 1) = 25(x + 3)

∴36x + 925x + 75

∴ 36x – 25 = 75 – 9

∴11x = 66

∴ x = 6

∴ x = 6 is the solution of the given equation.

∴ 4(3x – 4) = 5(x + 1)

∴ 12x – 16 = 5x + 5

∴ 12x – 5x = 5 + 16

∴ 7x = 21

∴ x = 3

∴ x = 3 ¡s the solution of the given equation.