Question 1200622: A quadratic polynomial of the form y=x^2+bx+c has x-intercepts at x=-7 and x=-3. What is the y-intercept of this parabola?
If anyone can help me solve this, I will gladly appreciate it.
Answer by ikleyn(52781)   (Show Source):
You can put this solution on YOUR website! .
A quadratic polynomial of the form y=x^2+bx+c has x-intercepts at x=-7 and x=-3.
What is the y-intercept of this parabola?
If anyone can help me solve this, I will gladly appreciate it.
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y-intercept is the value of this quadratic polynomial at x= 0.
Substitute x= 0 into the polynomial, and you will see that y-intercept is the value
of the coefficient "c".
According to Vieta's theorem, coefficient "c" (the constant term) is the product of the roots of the polynomial.
The roots are -7 and -3 (given), and their product is (-7)*(-3) = 21.
So, y-intercept is 21. ANSWER
Solved.
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