if y varies directly as x, if y=80 when x=32, find x if y=100

what is the answer?

Find the value of r so that the line that passes through each pair of points has the given slope:

(r, -8) (4, 1) and the slope of the line is 92

when x is 25 and y = 80 find x when y = 32

if y=3/4 find y when x=12

y varies directly as ---- y = kx, where k is a constant

given: y=80 when x = 32
80=32k
k = 80/32 = 5/2
so y = (5/2)x

if y = 100
100 = (5/2)x
x = 200/5 = 40

or in a simple ration like David has shown

32/80 = x2/100
x2 = 100(32/80) = 3200/80 = 40

if y=80 when x=32 when y=100

y=80 when x=32 when y=100

x1/y1=x2/y2