Question

Can someone help me out with this question plz

Answer 1

`\left(s\cdot t\right)\left(x\right)=2x^2+12x+16`

`\left(s-t\right)\left(x\right)=-x`

`\left(s+t\right)\left(4\right)=20`

Explanation:

Given functions are:

`s\left(x\right)=x+4`

`t\left(x\right)=2x+4`

Then
`\left(s\cdot t\right)\left(x\right)=s\left(x\right)\cdot t\left(x\right)`

or
`\left(s\cdot t\right)\left(x\right)=\left(x+4\right)\left(2x+4\right)`

or
`\left(s\cdot t\right)\left(x\right)=2x^2+4x+8x+16`

or
`\left(s\cdot t\right)\left(x\right)=2x^2+12x+16`

---------

Similarly

`\left(s-t\right)\left(x\right)=s\left(x\right)-t\left(x\right)`

or
`\left(s-t\right)\left(x\right)=\left(x+4\right)-\left(2x+4\right)=x+4-2x-4`

or
`\left(s-t\right)\left(x\right)=-x`

---------

Similarly

`\left(s+t\right)\left(4\right)=s\left(4\right)+t\left(4\right)=\left(4+4\right)+\left(2\left(4\right)+4\right)=\left(8\right)+\left(12\right)=20`

`\left(s+t\right)\left(4\right)=20`