Answer:
C and E
Step-by-step explanation:
given a quadratic in standard form
y = ax² + bx + c ( a ≠ 0 ) , then
• if a > 0 then the graph opens upward
• if a < 0 then the graph opens downward
----------------------------------------------------------------
A y = - x² + 9x with a < 0 then opens downward
B y = 10x - 5x² with a < 0 then opens downward
C y = (2x - 1)² = 4x² - 4x + 1 with a > 0 then opens upward
D y = (1 - x)(2 + x) = 2 - x - x² with a < 0 then opens downward
E y = x² - 8x - 7 with a > 0 then opens upward
