
Cheo L.
asked 11/07/20Need help for one function question
Let f(x) be a quadratic function such that f(x)=7 has one solution. The product of the roots of f(x) is 32. What is the sum of the roots of f(x)?
It would be greatly appreciated if the steps were included
2 Answers By Expert Tutors

Bradford T. answered 11/07/20
Retired Engineer / Upper level math instructor
I understood the question differently. That a solution of f(x) = 7
For a quadratic:
Let the roots be a and b. ab= 32
f(x) = (x-a)(x-b) = x2 -(a+b)x + ab = x2 -(a+b)x + 32 = 0
if f(x) = 7 --> x2 -(a+b)x +32 = 7 or g(x) = x2 - (a+b)x + 25 = 0
Factors of 25 are 1, 25, -1, -25
f(1) = 1 - (a+b) +32 = 7 --> (a+b) = -26
turns out for 1, -1, 25 and -25, (a+b) = -26

Andrew S. answered 11/07/20
B.S. in Electrical Engineering
Hi Chleo
If what I understand the question correctly. By solution of f(x) = 7 you mean that the a root is located at x = 7.
1.) I assume the first half of the quadratic is (x - 7)
2.) I mulitply 7 times x to equal 32
7x = 32
x = 32/7
3.) this means the other part to the quadratic is (x - 32/7)
4.) the sum of the roots are
7 + 32/7
7 *(7/7) + 32/7
49/7 +32/7
81/7
for fun the quadratic would be (x - 7) (x - 32/7) or x2 - (81/7)x + 32
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Touba M.
11/07/20