Answer:
y = 56
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
