Question

What value of a will yield a solution of (2,8) for the system?
y = ax
ax + y = 16

Answer 1

The value of a is 4 ⇒ D

Explanation:

In the system of equations

∵ y = ax ⇒ (1)

∵ ax + y = 16 ⇒ (2)

∵ The solution of the system is (2, 8)

∴ x = 2 and y = 8

→ To find the value of a substitute x by 2 and y by 8 in equation (1) or (2)

∵ y = ax

∵ y = 8 and x = 2

∴ 8 = a(2)

∴ 8 = 2a

→ Divide both sides by 2

∵
`(8)/(2)` =
`(2a)/(2)`

∴ 4 = a

∴ The value of a is 4