Question

A cubic polynomial function of degree f had leading coefficient 2 and constant term 7. If f(1)= 7 and f(2) = 9, what is f(-2)?

Answer 1

Please help I have a test tomorrow!

Answer 2

f(x) = ax^3 + bx^2 + cx + d


f(x) = 2x^3 + bx^2 + cx + 7


f(1) = 2(1)^3 + b(1)^2 + c(1) + 7


f(1) = 2(1) + b(1) + c(1) + 7


f(1) = 2 + b + c + 7


f(1) = b + c + 9


7 = b + c + 9


7-9 = b + c


-2 = b + c


b+c = -2


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f(x) = 2x^3 + bx^2 + cx + 7


f(2) = 2(2)^3 + b(2)^2 + c(2) + 7


f(2) = 2(8) + b(4) + c(2) + 7


f(2) = 16 + 4b + 2c + 7


f(2) = 4b + 2c + 23


9 = 4b + 2c + 23


9-23 = 4b + 2c


-14 = 4b + 2c


4b + 2c = -14

Answer 3

You now have the two equations


b+c = -2
4b + 2c = -14


which you can use to solve for b and c


Once you have the values of b and c, you can use them to find f(-2)

Answer 4

oh my lord thank you so much seriously thank you

Answer 5

np