Factor. if the expression cannot be factored, write cannot be factored. a) 12x +48 b) -6× -16 c) 13x + 9

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.