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 \(\displaystyle f(a+b)=~?\)