The function f(x) = 2x2 + 3x + 5, when evaluated, gives a value of 19. what is the function’s input value?

Let's called the input 'z'

When we plug 'z' in the function we get ;



And we know that, this is equal to 19, so ;



Let's rearrange the equation.



So we have a quadratic equation here.

We'll use this formula to solve it :



The formula is used in equation formed like this :



In our equation,

a=2 , b=3 and c=-14

Let's plug in the values in the formula to solve,



So,



So the input can be both, 2 and