9514 1404 393
Answer:
A, a = 4, b = -3, c = 3
Step-by-step explanation:
Expanding the left side gives ...
2x^2 -x -10 +ax^2 +bx +c
= (2 +a)x^2 +(b -1)x +(c -10)
Equating coefficients with terms on the right side gives ...
x^2: (2 +a) = 6 ⇒ a = 4 . . . . . . eliminates choice C
x: (b -1) = -4 ⇒ b = -3 . . . . . . . . eliminates choices B, D
constant: c -10 = -7 ⇒ c = 3 . . . confirms choice A
