Question

find an equation of variation where y varies directly as x one pair of values is y equals 80 when x equals 40​

Answer 1

y ∞ 2x, y = 2x

y varies directly as x

y ∞ x

y equals 80 when x equals 40​

y = kx

where k is a constant, when multiplied by x, gives you k.

80 = 40k

Solve to find k:

80/40 = k

80/40 = 2

k = 2

y = 2x