I know the 1st one.
Answer:
(x+3)(x-4) = x-12
Explanation:
This is called a foil method
1st: We multiply the two first numbers - x*x = 2x
2nd: We multiply the two outside numbers - x*(-4) = -4x
3rd: We multiply the two inside numbers - 3*x = 3x
4th: We multiply the two last numbers - 3*(-4) = -12
Then we combine them - 2x-4x+3x-12
Then we simplify - x-12
Hope this helped!