Due tomorrow i beg of. plzz do 6,7,8,9 i’m am desprate

If square root x = -7, then x= -49 true or false

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.

The width of a rectangle is half as long as the length. the rectangle has an area of 18 square feet. what are the length and width of the rectangle?