## Algebra: A Combined Approach (4th Edition)

Substitute 3, -6, and -9 for x, y, and z and solve the expression. 2$x^{2}$ - y + z = 2$(3^{2})$ - (-6) + (-9) = 2(9) - (-6) + (-9) = 18 - (-6) + (-9) = 24 + (-9) = 15