Answer:
a. [tex]8x^{2} -14x-15[/tex]
b. [tex](x+3)(x+2)[/tex]
Step-by-step explanation:
A. There are 3 methods (that I know of). The easiest method is the lattice multiplication, while the most commonly used is the FOIL method (First+Outer+Middle+Last)
For F, take the first terms of the 2 and multiply
[tex]4x*2x=8x^{2}[/tex]
For O, take the outer terms and multiply
[tex]4x*-5=-20x[/tex]
For I, take the inner terms and multiply
[tex]3*2x=6x[/tex]
For L, take the last terms and multiply
[tex]3*-5=-15[/tex]
After that, add all of them up
[tex]8x^{2} +(-20x)+6x+(-15)=8x^{2}-14x-15[/tex]
B. Since the equation is in the form x^2+bx+c,
[tex](x+?)(x+?)[/tex]
Now we need to find 2 numbers that will add up to 5 and multiply to 6.
Here are some of the combinations of numbers that multiply to 6
3*2
1*6
-3*-2
-1*-6
3 and 2 add up to 5 so:
[tex](x+3)(x+2)[/tex]
