Question

When iris subtract -12-(-12), she got a difference of -24 is her answer correct? If not what mistake did she make?

Answer 1

Gaira made a mistake when substituting the value –7.5 in for x. She multiplied both terms of the expression by –7.5 when she should have only multiplied –3.8 by –7.5. The correct answer is 34.5.

Answer 2

incorrect as - 12 - (- 12) = 0

note that -(- 12) is equivalent to + 12

-12 -(- 12) = - 12 + 12 = 0