A help please

What are the solutions of the system? solve by graphing. y = -x^2 - 3x + 2 y = -2x + 2

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'

How many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.) how many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.)