Aubrey C. answered 02/28/21
Compassionate & Engaging Math Tutor with an Arts Background
When we're factoring, a good trick to use is to look for numbers that "multiply to c, add to b", where b and c are the coefficients in the standard form ax2+bx+c. It gets just slightly trickier when we have a coefficient for a as well, but not by much.
I like to start by writing out the two parenthesis that will hold my linear terms: ( )( )
Then, if I don't want to use the quadratic formula or anything like that, it's often quickest to just guess and check. Since the first terms have to multiply to 49x2, I'm guessing they're probably 7x and 7x.
(7x )(7x )
The last terms have to multiply to 4, so I'm going to guess +2 and +2. Then I'll check with FOIL method (First, Outside, Inside, Last) to see if I get +28x as my middle term.
(7x+2)(7x+2) = 49x2+14x+14x+4 = 49x2+28x+4
It worked! So my factoring is done.