Wednesday

November 26, 2014

November 26, 2014

Posted by **Amie** on Tuesday, October 4, 2011 at 12:27am.

f(x) = −x2 + 10x

- Pre-Calculus -
**drwls**, Tuesday, October 4, 2011 at 6:43amAll you have done is define f(x).

There is no "solution"

If you had written

f(x) = (any constant),

there would be a solution.

- Pre-Calculus -
**Steve**, Tuesday, October 4, 2011 at 11:24amNow, if you want to solve f(x) = 0,

f(x) = -2x(x-5)

so, f=0 when either factor is zero. This is why we always set f(x) = 0 to solve for x, because the only time a product of numbers is zero is when one of them is zero. If we had -2x(x-5) = 12, well, that doesn't help us because there are lots of numbers that multiply to equal 12. But if the product is zero, then one of the factors must be zero.

so, x=0 or x=5 will make f(x) = 0

**Answer this Question**

**Related Questions**

Pre-Calculus - Find all the real zeros of the polynomial. Use the quadratic ...

calculus - A function f(x) is said to have a removable discontinuity at x=a if: ...

calculus - For what values of a and b that make the function f continuous ...

Calculus - An important problem in mathematics is that of root finding: that is...

calculus - f(x,y)=x^2+2y^2 use the gradient vector f(5, 1) to find the tangent...

Calculus - Given f(x)=−2x^3 -3x + 1, the value of the derivative of the ...

Pre-Calculus - How do I write the quadratic function f(x) = 1/2 (6x^2 - 24x + 22...

Math (Quadratic Function) - Suppose p(x)=ax^2+bx+c is a quadratic polynomial ...

Pre Calc (For Reiny) - Thanks so much your method worked perfectly! My solution ...

Math (Pre-Calculus) - Can someone help me with this? Thanks! Find the zeros of ...