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

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

option (b) is correct

step-by-step explanation:

to find the solution of this system, we need to convert it into reduced row-echelon form. we have,

after applying row operations r2 -> r2/2 and r3 -> r3/3, we get,