Solve the equation x^2 – 4x – 31=-2x + 25 to the nearest tenth.
2 answers:
Answer:
x = -6.5, x = 8.5
Step-by-step explanation:
The given equation ...
x^2 -4x -31 = -2x +25
can be rewritten to a form that facilitates completing the square:
x^2 -2x = 56 . . . . . add 2x+31
x^2 -2x +1 = 57 . . . add 1 to complete the square
(x -1)^2 = 57 . . . . . write the left side as a square
x -1 = ±√57 . . . . . take the square root
x = 1 ±√57 ≈ {-6.5, 8.5} . . . . . add 1, evaluate
Solutions are near x = -6.5 and x = 8.5.
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