The equivalent expression is -2x + 9
Explanation:
5x + 9 + (-7x) = _ x + 9
we expand the parenthesis:
Multiplication of opposite signs give negative number.
5x + 9 - 7x = _ x + 9
collect like terms"
5x and -7x are like terms
5x - 7x = -2x
5x - 7x + 9 = -2x + 9
The left hand side must be equal to the right hand side.
As a result, comparing Left and right side:
the missing number on the right hand side is -2
The equivalent expression is -2x + 9
