
David W. answered 03/03/16
Tutor
4.7
(90)
retired
Remember F-O-I-L (First-Outside-Inside-Last).
When an expression like (ax+b)(cx+d) is expanded using the Distributive Property (twice) it is:
(ax+b)(cx+d)
ax(cx+d) + b(cx+d)
acx2 + axd + bcx + bd
F O I L
acx2 + (ad+bc)x + bd
"To factor" means to find the values that were multiplied to get the expression. What factors produced:
x2 -2x + 1
We need to find the values of: a,b,c,d
ac = 1
(ad+bc)= -2
bc = 1
For a perfect square: (ax+b)(ax+b), this is a2=1, 2ab=-2, b2=1. So, a=1 and b=-1, right? (x-1)2
PLZ try to learn the various methods for finding numbers that add to produce a value and multiply to produce another value. Also, learn to use the Quadratic Formula.
x2 - 2x + 1 = 0
Using the Quadratic Formula, the values of x that satisfy the equation are: 1 and 1 which means
(x - 1)(x - 1) = 0
So, a=1, b=-1. c=1, d=-1
This is a perfect square (which is likely the topic you are currently studying.)
To check: Apply F-O-I-L to (x - 1)(x - 1):
F O I L
x2 - x - x + 1
x2 -2x + 1 Check!
When an expression like (ax+b)(cx+d) is expanded using the Distributive Property (twice) it is:
(ax+b)(cx+d)
ax(cx+d) + b(cx+d)
acx2 + axd + bcx + bd
F O I L
acx2 + (ad+bc)x + bd
"To factor" means to find the values that were multiplied to get the expression. What factors produced:
x2 -2x + 1
We need to find the values of: a,b,c,d
ac = 1
(ad+bc)= -2
bc = 1
For a perfect square: (ax+b)(ax+b), this is a2=1, 2ab=-2, b2=1. So, a=1 and b=-1, right? (x-1)2
PLZ try to learn the various methods for finding numbers that add to produce a value and multiply to produce another value. Also, learn to use the Quadratic Formula.
x2 - 2x + 1 = 0
Using the Quadratic Formula, the values of x that satisfy the equation are: 1 and 1 which means
(x - 1)(x - 1) = 0
So, a=1, b=-1. c=1, d=-1
This is a perfect square (which is likely the topic you are currently studying.)
To check: Apply F-O-I-L to (x - 1)(x - 1):
F O I L
x2 - x - x + 1
x2 -2x + 1 Check!