Question

4x+2y=20 -8x-3y=16 what is y

Answer 1

y = 56

Step-by-step explanation:

We label each of the given equations as follows;

4·x + 2·y = 20...(1)

-8·x - 3·y = 16...(2)

Therefore, we are given a simultaneous equation, question

We make 'x' the subject of both equations and equate the result to find the value of 'y' as follows;

For equation (1)

4·x + 2·y = 20

∴ x = (20 - 2·y)/4 = 5 - y/2

x = 5 - y/2

For equation (2), we have;

-8·x - 3·y = 16

∴ x = (16 + 3·y)/(-8) = -2 - 3·y/8

x = -2 - 3·y/8

Equating the two equations of 'x', gives;

5 - y/2 = -2 - 3·y/8

7 = y/2 - 3·y/8 = (4·y - 3·y)/8 = y/8

∴ 7 = y/8

y = 7 × 8 = 56

y = 56