Question

if 2x:3y =4:9 , then find 5x+7y/7x+5y?

Answer 1

Answer:

1.5

Step-by-step explanation:

A pair of simultaneous equations.

3x + 5y = 9 …………eqn. (i)

5x + 3y = 7 …………..eqn. (ii)

Solving a pair of simultaneous equations, using the elimination method

3x + 5y = 9 …………eqn. (i) x 5

5x + 3y = 7 ……… eqn. (ii) x 3

15x + 25y = 45 ……….. eqn. (iii)

15x+ 9y = 21 …………… eqn. (iv)

Subtract eqn. (iv) from eqn. (iii)

16y = 24

y = 24/16 = 1.5

Substitute y into equation (iv)

15x + 9(1.5) = 21

15x + 13.5 = 21

15x = 7.5

x = 7.5/15 = 0.5

x = 0.5 ; y = 1.5