Question

Given f(x) = –x2 + 10x – 16 and g(x) = |11 – 2x2 |, find 2•f(9) – g(–5)

Answer 1

Dear friend,
Substitute the the values of x in f(x) and g(x) respectively ....
You will get f(9)=-7 and g(-5)=39
Then proceed with the expression 2•f(9)-g(-5)
Finally the answer becomes -53

Answer 2

f(x) = –x² + 10x – 16  

g(x) = |11 – 2x² |

FInd f(9) :

f(x) = –x² + 10x – 16  

f(9) = -(9)² + 10(9) - 16 = -7

Find g(-5):

g(x) = |11 – 2x² |

g(-5) = | 11 - 2(-5)² |  = | -39| = 39

Find 2 x f(9) – g(–5):

2 x f(9) – g(–5) = 2 (-7) - (39) = -53

Answer: -53