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6x2+8=20x-8 the 6x is squared

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2 Answers

Hi Roseland;
6x2+8=20x-8
Let's move everything to one side.
Let's subtract (20x-8) from both sides...
6x2+8-(20x-8)=(20x-8)-(20x-8)
6x2+8-20x+8=0
Let's combine like terms...
6x2-20x+16=0
Let's factor-out 2...
2(3x2-10x+8)=0
The parenthetical equation must equal zero.  Therefore...
3x2-10x+8=0
For the FOIL...
FIRST must be (3x)(x)=3x2
OUTER and INNER must add-up to -10x
LAST must be (8)(1) or (1)(8) or (4)(2) or (2)(4) and both numbers must be negative to render the result of -10x and +8.
(3x-4)(x-2)=0
Let's FOIL...
FIRST...(3x)(x)=3x2
OUTER...(3x)(-2)=-6x
INNER...(-4)(x)=-4x
LAST...(-4)(-2)=8
3x2-6x-4x+8=0
3x2-10x+8=0
(3x-4)(x-2)=0
Either or both parenthetical equations must equal zero...
3x-4=0
3x=4
x=4/3
x-2=0
x=2