If f=5, what is the value of 2f^2+8f-5?

May 30, 2017

$85$

Explanation:

$2 {f}^{2} + 8 f - 5$

$f = 5$

We can now substitute $f$ for $5$ in the question.

$2 \times {5}^{2} + 8 \times 5 - 5$

$2 \times 25 + 40 - 5$

$50 + 40 - 5$

$90 - 5$

$85$

May 30, 2017

$85$.

Explanation:

First, plug the number in.
$2 \cdot {5}^{2} + 8 \cdot 5 - 5$

Then, follow the order of operations.

There are no grouping symbols, so do exponents first.
$2 \cdot$25 $+ 8 \times 5 - 5$

Multiplication is next:
50 $+ 40 - 5$