Math Problem: Let f(x) = 4x − 3. If f(a) = 9 and f(b) = 5, then what is f(a + b)

[lsmith130]

Math Problem: Let f(x) = 4x − 3. If f(a) = 9 and f(b) = 5, then what is f(a + b)

Let f(x) = 4x − 3. If f(a) = 9 and f(b) = 5, then what is f(a + b) ?

 

[pka]

Let f(x) = 4x − 3. If f(a) = 9 and f(b) = 5, then what is f(a + b) ?

$\displaystyle f(a)=4a-3=9$ so $\displaystyle 4a=~?$

$\displaystyle f(b)=4b-3=5$ so $\displaystyle 4b=~?$

$\displaystyle f(a+b)=4(a+b)-3$ so $\displaystyle f(a+b)=~?$