Question

If f(x)=2x-5, find x when f(x)=13

this is function notation

Answer 1

`f(x)=2x-5\\ \\ f(x)=13 \rightarrow 2x-5=13\\ \\ 2x=13+5\\ \\ 2x=18\\ \\ x=(18)/(2)\\ \\ \boxed{x=9}`

Answer 2

`f(x)=2x-5;\ f(x)=13\\\Downarrow\\2x-5=13\\2x-5+5=13+5\\2x=18\\2x:2=18:2\\\underline{\underline{x=9}}`