Question

Solve 2x2 - 8x = -7 Which of the following is a solution of x2 + 5x = -2?

Answer 1

2x² - 8x = -7
2x² - 8x + 7 = -7 + 7
2x² - 8x + 7 = 0
x = -(-8) +/- √((-8)² - 4(2)(7))
                      2(2)
x = 8 +/- √(64 - 56)
                 4
x = 8 +/- √(8) 
             4
x = 8 +/- 2.828
               4
x = 2 +/- 0.707
x = 2 + 0.707      x = 2 - 0.707
x = 2.707            x = 1.293
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x² + 5x = -2
x² + 5x + 2 = -2 + 2
x² + 5x + 2 = 0
x = -5 +/- √(5² - 4(1)(2))
                  2(1)
x = -5 +/- √(25 - 8)
                  2
x = -5 +/- √(17)
               2
x = -5 +/- 4.123
                2
x = -2.5 +/- 2.0615
x = -2.5 + 2.0615      x = -2.5 - 2.0615
x = 0.4385                x = -4.5615