 # How do you find the zeroes for f(x)=x^{2}-9x-70? Anderson Melton 2022-01-23 Answered
How do you find the zeroes for $f\left(x\right)={x}^{2}-9x-70$?
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Step 1
We need to think of two numbers, that, when I add them, sum up to -9, and when I multiply them, have a product of -70. Since the product is negative, we know the signs must be different.
Through some thought, we arrive at -14 and 5 as our two numbers, because
$-14+5=-9$ and
$-14×5=-70$
Thus, our equation is as follows:
$\left(x-14\right)\left(x+5\right)=0$
To find the zeroes, we take the opposite signs to get
$x=14$ and $x=-5$
###### Not exactly what you’re looking for? Nevaeh Jensen
Step 1
$f\left(x\right)={x}^{2}-9x-70=0$
To solve f(x), find 2 numbers (real roots) knowing the sum $\left(-b=9\right)$ and the product $\left(c=-70\right)$. They are: - 5 and 14.
Note . This method avoids proceeding the lengthy factoring by grouping and solving the 2 binomials.