Who is really good with math? I need serious help i am failing math

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

What is the explicit formula for this sequence? -7, -4, -1, 2, a.) an = 8 + (b - 1)3 b.) an = -7 + (n - 1)3 c.) an = 3 + (n -1) (-7) d.) an = -7 + (n - )

Given the numbers c = –3 and d = 4, which statement is true? a. |–c| = 3 and |–d| = –4 b. |–c| = 3 and –|d| = –4 c. –|c| = –4 and –|d| = 3 d. |–c| = 3 and –|d| = 4