Question 141031
solve {{{x^2+3x-4=0}}} by "completing the square", 
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x^2+3x+? = 4+?
Square [(1/2)3] and add it to the left and right side to get:

x^2+3x + [(1/2)3]^2 = 4 + [(1/2)3]^2

Simplify both sides:

(x+(3/2))^2 = 4 + (3/2)^2

(x+(3/2))^2 = 25/4

Take the square root of both sides to get:

(x+(3/2)) = +- 5/2

x = (-3/2) + (5/2) or x = (-3/2) - (5/2)

x = 1 or x = 4
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Cheers,
Stan H.