Question

Please help! important!! worth 30 points

Answer 1

The answer is C if u do the question right

Answer 2

Answer:

IS C

Step-by-step explanation:

(2x+1)(2x-1)

apply different of two formula :(a+b)(a-b)=a^2-b^2

a=2x, b=1

=(2x)^2-1^2

Simplify (2x)^2- 1^2: 4x^2-1

(2x^2)-1^2

apply rule 1^a=1

1^2=1

=(2x)^2-1

(2x)^2=4x^2

apply exponent rule:(a·b)^n=a^nb^n

=2^2x^2

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2^2=4

=4^2

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4x^2-1

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(x-2)(x+3)

apply FOIL method:(a+b)(c+d)=ac+ad+bc+bd

a=x, b=-2, c=x, d=3

=xx+x·3+(-2)x+(-2)·3

apply minus-plus rules

+(-a)=-a

xx+3x-2x-2·3

add similar elements:3x-2x=x

=xx+x-2·3

apply exponent rule:a^b·a^c=a^b+c

=x^2+x-2·3

multiply the numbers:2·3=6

=x^2+x-6

distribute parenthese

=(x^2)-(x)-(-6)

apply minus-plus rule

= -x^2-x=6

4x^2-1=x^2-x+6

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4x^2-1=x^2-x+6

switch sides =-x^2-x+6=4x^2-1

add 1 to both sides -x^2-x+6+1=4x2-1+1

simplify -x^2-x+7=4x2

subtract 4x^2 from both sides

-x^2-x+7-4x^2-4x^2

simplify -5x^2-x+7=0

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a=-5, b=-1, c=7   x1,2=√(-1)^2-4(-5)7

 #1       x=-1(-1)+√(-1)^2-4(-5)7 ÷ 2(-5)

            =-1+√141 ÷ 10

#2        x=-(-1)-√(-1)^2-4(5)7 ÷ 2(-50

           =√141-1 ÷ 10

x=-1+√141 ÷10 & -1√141 ÷10   = answer C.