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A) The function f is defined by : f(x) = x2+ax+b
a and b are constants.
It is known that: f(0) = 7 and f(-2) = 17
Find the values of a and b.

B) Use the values of a and b to solve this equation: f(x) = 35
x = __ or x = __?

Respuesta :

Answer:

A. a = -3 and b = 7.

B. x = -4 or x = 7.

Step-by-step explanation:

A)

f(0) = 0^2 + a(0) + b =  7

So b = 7.

f(-2) = (-2)^2- 2a + 7 = 17

4 - 2a = 17 - 7

4 - 2a = 10

-2a = 10 - 4 = 6

-2a = 6/-2

a = -3.

B)

Substituting a = -3 and b = 7 we get:-

x^2 - 3x + 7 = 35

x^2 - 3x - 28 = 0

(x - 7)(x + 4) = 0

x - 7 = 0 or x + 4 = 0

x = -4 or x = 7.

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