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what is x+2 =8

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1 Answer

I think the curly bracket { is a modulus written like |

Questions of this type will have two solutions as indicated in the solution choices.

Remember that modulus changes negative to positive values.

1st solution: put a negative sign around (x+2) and solve

-(x+2)  = 8

taking negative into the parenthesis,

-x -2 = 8

i.e. - x = 10 or x = -10

2nd solution: solve with the positive sign around (x+2)

x+2 = 8 i.e. without the negative sign

x =  8 - 2 = 6

so solution b) ( 6,-10) is the right answer.

 

The other approach is to squaring method;

Square both sides of the equation:

(x+2)^2 = 8^2

x^2 + 4x + 4 = 64

bringing 64 to the left of the equation,

x^2 + 4x - 60 = 0 

Factorizing the above equation

x^2 + 10x - 6x - 60 = 0

(x+10) (x-6) = 0

x+10 = 0 or x = -10

or

x - 6 = 0 or x = 6

Again, b) is the right answer (6, -10)