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

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Answer 1 · 2017-05-30T23:27:39

#85#

#2f^2 + 8f - 5#

#f = 5#

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

#2 xx 5^2 + 8 xx 5 - 5#

#2 xx 25 + 40 - 5#

#50 + 40 - 5#

#90 - 5#

#85#

Answer 2 · 2017-05-30T23:32:35

#85#.

First, plug the number in.
#2 * 5^2+8 * 5-5#

Then, follow the order of operations.

There are no grouping symbols, so do exponents first.
#2 *#25 #+8 xx5-5#

Multiplication is next:
50 #+40 - 5#

Finally, addition and subtraction.
85