Question
$$(x+2)(x-1) = 3$$
Answer
$$ \begin{matrix}x_1 = -\dfrac{ 1 }{ 2 }-\dfrac{\sqrt{ 21 }}{ 2 } & x_2 = -\dfrac{ 1 }{ 2 }+\dfrac{\sqrt{ 21 }}{ 2 } \\[1 em] \end{matrix} $$
Explanation
$$ \begin{aligned} (x+2)(x-1) &= 3&& \text{simplify left side} \\[1 em]x^2-x+2x-2 &= 3&& \\[1 em]x^2+x-2 &= 3&& \text{move all terms to the left hand side } \\[1 em]x^2+x-2-3 &= 0&& \text{simplify left side} \\[1 em]x^2+x-5 &= 0&& \\[1 em] \end{aligned} $$
$ x^{2}+x-5 = 0 $ is a quadratic equation.
You can use step-by-step quadratic equation solver to see a detailed explanation on how to solve this equation.
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