If y varies inversely as x and y=12 when x=-4, find x when y=6.4. (write only the value of x)

Answer 1

When y varies inversely as x, this can be written as y = k/x where k is a constant.

k can be found by substituting x = -4 and y = 12 and solve for k.

k = -4 * 12 = -48

To find x when y = 6.4, solve the equation y = -48 / x for x which gives x = -48 / 6.4

x = -7.5