1-9 uses the distributive property
The distributive just breaks the quantity apart.
a( b + c) = ab + ac
Multiply a times each number in the parentheses.
Now using real numbers for #1: 3(2x - 5)
Multiply 3 times 2x, = 6x
Now multiply 3 times -5 = -15
Now you put the two terms you got and you get 6x - 15