Solve for x
x=-62
x=60
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2x^{2}+4x+4-7444=0
Subtract 7444 from both sides.
2x^{2}+4x-7440=0
Subtract 7444 from 4 to get -7440.
x^{2}+2x-3720=0
Divide both sides by 2.
a+b=2 ab=1\left(-3720\right)=-3720
To solve the equation, factor the left hand side by grouping. First, left hand side needs to be rewritten as x^{2}+ax+bx-3720. To find a and b, set up a system to be solved.
-1,3720 -2,1860 -3,1240 -4,930 -5,744 -6,620 -8,465 -10,372 -12,310 -15,248 -20,186 -24,155 -30,124 -31,120 -40,93 -60,62
Since ab is negative, a and b have the opposite signs. Since a+b is positive, the positive number has greater absolute value than the negative. List all such integer pairs that give product -3720.
-1+3720=3719 -2+1860=1858 -3+1240=1237 -4+930=926 -5+744=739 -6+620=614 -8+465=457 -10+372=362 -12+310=298 -15+248=233 -20+186=166 -24+155=131 -30+124=94 -31+120=89 -40+93=53 -60+62=2
Calculate the sum for each pair.
a=-60 b=62
The solution is the pair that gives sum 2.
\left(x^{2}-60x\right)+\left(62x-3720\right)
Rewrite x^{2}+2x-3720 as \left(x^{2}-60x\right)+\left(62x-3720\right).
x\left(x-60\right)+62\left(x-60\right)
Factor out x in the first and 62 in the second group.
\left(x-60\right)\left(x+62\right)
Factor out common term x-60 by using distributive property.
x=60 x=-62
To find equation solutions, solve x-60=0 and x+62=0.
2x^{2}+4x+4=7444
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.
2x^{2}+4x+4-7444=7444-7444
Subtract 7444 from both sides of the equation.
2x^{2}+4x+4-7444=0
Subtracting 7444 from itself leaves 0.
2x^{2}+4x-7440=0
Subtract 7444 from 4.
x=\frac{-4±\sqrt{4^{2}-4\times 2\left(-7440\right)}}{2\times 2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 2 for a, 4 for b, and -7440 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-4±\sqrt{16-4\times 2\left(-7440\right)}}{2\times 2}
Square 4.
x=\frac{-4±\sqrt{16-8\left(-7440\right)}}{2\times 2}
Multiply -4 times 2.
x=\frac{-4±\sqrt{16+59520}}{2\times 2}
Multiply -8 times -7440.
x=\frac{-4±\sqrt{59536}}{2\times 2}
Add 16 to 59520.
x=\frac{-4±244}{2\times 2}
Take the square root of 59536.
x=\frac{-4±244}{4}
Multiply 2 times 2.
x=\frac{240}{4}
Now solve the equation x=\frac{-4±244}{4} when ± is plus. Add -4 to 244.
x=60
Divide 240 by 4.
x=-\frac{248}{4}
Now solve the equation x=\frac{-4±244}{4} when ± is minus. Subtract 244 from -4.
x=-62
Divide -248 by 4.
x=60 x=-62
The equation is now solved.
2x^{2}+4x+4=7444
Quadratic equations such as this one can be solved by completing the square. In order to complete the square, the equation must first be in the form x^{2}+bx=c.
2x^{2}+4x+4-4=7444-4
Subtract 4 from both sides of the equation.
2x^{2}+4x=7444-4
Subtracting 4 from itself leaves 0.
2x^{2}+4x=7440
Subtract 4 from 7444.
\frac{2x^{2}+4x}{2}=\frac{7440}{2}
Divide both sides by 2.
x^{2}+\frac{4}{2}x=\frac{7440}{2}
Dividing by 2 undoes the multiplication by 2.
x^{2}+2x=\frac{7440}{2}
Divide 4 by 2.
x^{2}+2x=3720
Divide 7440 by 2.
x^{2}+2x+1^{2}=3720+1^{2}
Divide 2, the coefficient of the x term, by 2 to get 1. Then add the square of 1 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+2x+1=3720+1
Square 1.
x^{2}+2x+1=3721
Add 3720 to 1.
\left(x+1\right)^{2}=3721
Factor x^{2}+2x+1. In general, when x^{2}+bx+c is a perfect square, it can always be factored as \left(x+\frac{b}{2}\right)^{2}.
\sqrt{\left(x+1\right)^{2}}=\sqrt{3721}
Take the square root of both sides of the equation.
x+1=61 x+1=-61
Simplify.
x=60 x=-62
Subtract 1 from both sides of the equation.
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