Asked by MV
How do I create a quadratic equation that passes through the points (-1,2),(1,7),(4,5)?
Answers
Answered by
Steve
y = ax^2 + bx + c
a - b + c = 2
a + b + c = 7
16a + 4b + c = 5
subtract 1st from 2nd:
2b = 5
b = 5/2
a + 5/2 + c = 7
16a + 10 + c = 5
subtract 1st from 2nd:
15a + 15/2 = -2
15a = -19/2
a = -19/30
-19/30 + 5/2 + c = 7
c = 154/30
y = -19/30 x^2 + 5/2 x + 77/15
a - b + c = 2
a + b + c = 7
16a + 4b + c = 5
subtract 1st from 2nd:
2b = 5
b = 5/2
a + 5/2 + c = 7
16a + 10 + c = 5
subtract 1st from 2nd:
15a + 15/2 = -2
15a = -19/2
a = -19/30
-19/30 + 5/2 + c = 7
c = 154/30
y = -19/30 x^2 + 5/2 x + 77/15