The variables x and y vary inversely, and y = 2 when x = 1. Write an equation that relates x and y. Then find y when x = –8.

Answer 1

Varies inversely means:

y = k/x

where k is a constant. The constant (k) can be found by solving the above equation for k:

yx = k

Now we are given y = 2 when x= 1. Substituting:

yx = k

2·1 = k

2 = k

the equation is:

y = 2/x

Plug in x = -8 to find the y-value.