Question

Use the function f(x)=2x³ +4 and g(x)=5x to find the value of expression f(3) - 2g(3).

Answer 1

Thanks for asking this interesting question.

• f(x)=2x^3+4
• g(2)=5x

Find f(3)

`\\ \sf\longmapsto 2(3)^3+4`

`\\ \sf\longmapsto 2(27)+4`

`\\ \sf\longmapsto 54+4`

`\\ \sf\longmapsto 58`

Find g(3)

`\\ \sf\longmapsto 5(3)`

`\\ \sf\longmapsto 15`

Now

`\\ \sf\longmapsto f(3)-2g(3)`

`\\ \sf\longmapsto 58-2(15)`

`\\ \sf\longmapsto 58-30`

`\\ \sf\longmapsto 28`