How do I work question 17?

Use the distributive property -7(-2x+u-2)

Consider u = {x|x is a negative real number}which is an empty set? o {x|x eu and x has a negative cube root}o {x|x eu and x has a negative square root}{x|x eu and x is equal to the product of a positive number and -1}{x|x eu and x is equal to the sum of one negative and one positive number?

Find the solution of this system of equations -7x+y=-20 9x-3y=36