SOLUTION: Please help me find the value of x in this equation. x^2+2x=8

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Question 93704This question is from textbook Geometry
: Please help me find the value of x in this equation.
x^2+2x=8 This question is from textbook Geometry

Found 2 solutions by praseenakos@yahoo.com, jayanthihemkos@yahoo.com:
Answer by praseenakos@yahoo.com(507) (Show Source):
You can put this solution on YOUR website!
Question:

Please help me find the value of x in this equation.
x^2+2x=8

Answer :

Subtract 8 from both sides( then it will be in the standard form of a quadratic equation)

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You can solve it by using quadratic formula as well as splitting the middle term.

Method of splitting middle term:

Here you need to find out two numbers whose sum is +2 (coefficient of x) and whose product is -8( that is the constant term)

Such two numbers are +4 and -2

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Now group the terms.

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Now take out the common terms from each group.

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Here (x + 4 ) is common in both the groups, so you can take it outside...

==> (x + 4 ) ( x - 2) = 0

==> either (x + 4 ) = 0 or ( x - 2) = 0

==> (x + 4 ) = 0 ==> x = -4 and

( x - 2) = 0 ==> x = 2

So the value of x is either or

Hope you found the explanation useful.

Regards.

Praseena.

Answer by jayanthihemkos@yahoo.com(87) (Show Source):
You can put this solution on YOUR website!
x^2+2x=8
x^2 +2x -8 = 0
This can be factorised using middle term factorisation.
x^2 +4x - 2x -8 = 0
==> x(x + 4) -2(x + 4) = 0 (taking common factor)
==> (x-2) (x+4) = 0
==> x-2 = 0
==> x-2+ 2=0 +2
==> x= 2
now consider x +4 = 0
==> x + 4-4 = 0-4
==> x = -4
Hence x = 2 and x = -4 is the solution for the equation.