Because the slope is 0, it means its a horizontal line. because the horizontal is on 3, then it doesnt matter what x is as long as y is 3 if that makes any sense.
as the -32 is in bracket so we must look at it first. then the (-) is multiplied with the + outside bracket which is +×(-)=- . so it will be plus i.e. 22-32 and final step subtract it. the answer is -10.