SOLUTION: In the xy-plane, if the parabola with equation y=axsquared+bx+c, where a, b, and c are constants, passes through the point (-1,1), which of the following must be true? A) a-b=1 B

Algebra ->  Coordinate-system -> SOLUTION: In the xy-plane, if the parabola with equation y=axsquared+bx+c, where a, b, and c are constants, passes through the point (-1,1), which of the following must be true? A) a-b=1 B      Log On


   

Question 996378: In the xy-plane, if the parabola with equation y=axsquared+bx+c, where a, b, and c are constants, passes through the point (-1,1), which of the following must be true?
A) a-b=1
B) -b+c=1
C) a+b+c=1
D) a-b+c=1
Answer by ikleyn(52787) About Me  (Show Source):
You can put this solution on YOUR website!
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You are given that the polynomial  y = ax%5E2+%2B+bx+%2B+c  has the value  y=1  at  x=-1.

It means that  (substitute this value of  x=-1  into the polynomial)

1 = y = a%2A%28-1%29%5E2+%2B+b%2A%28-1%29+%2B+c = a*1 -b + c = a - b + c.

Again:   a - b + c = 1.

It is case  D).