Answer:
13. 5(m-2)
Your multiplying the number outside the bracket by the ones inside the brackets
so 5×m= 5m
5×-2= -10
so the answer is 5m-10
14. -3×m= -3m
-3×4=-12
= -3m-12
15. h×h= h²
h×-2= -2h
=h²-2h
16. -2z + 16
17. 8y+16
18. a²+ 3a
19. 2m² + 8m
20. -4x²+40x
