Question

Explain how to isolate the variable in this equation -2/5x+7=15

Answer 1

`x = -20`

Explanation:

Use inverse operations and simplification to isolate the variable in the equation.

`-(2)/(5)x + 7 = 15\\-7\\\\-(2)/(5)x = 8\\`

Now divide the equation by
`(-(2)/(5))` remember, dividing a fraction is the same as multiplying by the reciprocal. The reciprocal of a fraction is when one switches the places of the numerator (number on top of a fraction bar), and the denominator (number on the bottom of the fraction bar).

`-(2)/(5)x = 8\\`

÷
`-(2)/(5)`

`x = 8 * (-(5)/(2))`

Simplify,

`x = 4 *(- 5)\\\\ x= -20`