Question

The value of y varies directly with x, and y = −10 when x = 40. Identify the value of y when x = −5.

Answer 1

-10/40 = y / -5
cross multiply
(40)(y) = (-5)(-10)
40y = 50
y = 50/40
y = 5/4 <===

Answer 2

The value of y when x is -5 is (-10 * -5) 40 = 1.25
y=1.25