Question

x-7=-7
$x - 7 = - 7$

Answer 1

Vamos la, acho que a resposta e essa:

x-7=-7
x=-7+7
x=0

Answer 2

$\large\displaystyle\sf x-7=-7$

$\large\displaystyle\sf x=-7+7$

$\large\displaystyle\text{ \boxed{\boxed{\sf x=0}} }$