Question 205246
A(x) = (2x-1)(x+2) is correct! However (2x-1)(x+2) is NOT equal to 3x-2!!.<br>
To multiply (2x-1)(x+2) you must use a method called FOIL (or something equivalent to it). The "F" stands for first:
{{{2x*x = 2x^2}}}
The "O" stands for outside:
{{{2x * 2 = 4x}}}
The "I" stands for inside:
{{{-1 * x = -x}}}
The "L" stands for last:
{{{-1 * 2 = -2}}}<br>
All together we get:
{{{A(x) = (2x-1)(x+2) = 2x^2 + 4x + (-x) + (-2) = 2x^2 + 3x + (-2)}}}
Now we can find A(5):
{{{A(5) = (2x-1)(x+2) = 2(5)^2 + 3(5) + (-2) = 2*25 + 3*5 + (-2) = 50 + 15 + (-2) = 63}}}