Solve for x
x=-3000
x=2500
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60000\left(-500\right)+x\times 2000=-4xx
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by x.
60000\left(-500\right)+x\times 2000=-4x^{2}
Multiply x and x to get x^{2}.
-30000000+x\times 2000=-4x^{2}
Multiply 60000 and -500 to get -30000000.
-30000000+x\times 2000+4x^{2}=0
Add 4x^{2} to both sides.
-7500000+500x+x^{2}=0
Divide both sides by 4.
x^{2}+500x-7500000=0
Rearrange the polynomial to put it in standard form. Place the terms in order from highest to lowest power.
a+b=500 ab=1\left(-7500000\right)=-7500000
To solve the equation, factor the left hand side by grouping. First, left hand side needs to be rewritten as x^{2}+ax+bx-7500000. To find a and b, set up a system to be solved.
-1,7500000 -2,3750000 -3,2500000 -4,1875000 -5,1500000 -6,1250000 -8,937500 -10,750000 -12,625000 -15,500000 -16,468750 -20,375000 -24,312500 -25,300000 -30,250000 -32,234375 -40,187500 -48,156250 -50,150000 -60,125000 -75,100000 -80,93750 -96,78125 -100,75000 -120,62500 -125,60000 -150,50000 -160,46875 -200,37500 -240,31250 -250,30000 -300,25000 -375,20000 -400,18750 -480,15625 -500,15000 -600,12500 -625,12000 -750,10000 -800,9375 -1000,7500 -1200,6250 -1250,6000 -1500,5000 -1875,4000 -2000,3750 -2400,3125 -2500,3000
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 -7500000.
-1+7500000=7499999 -2+3750000=3749998 -3+2500000=2499997 -4+1875000=1874996 -5+1500000=1499995 -6+1250000=1249994 -8+937500=937492 -10+750000=749990 -12+625000=624988 -15+500000=499985 -16+468750=468734 -20+375000=374980 -24+312500=312476 -25+300000=299975 -30+250000=249970 -32+234375=234343 -40+187500=187460 -48+156250=156202 -50+150000=149950 -60+125000=124940 -75+100000=99925 -80+93750=93670 -96+78125=78029 -100+75000=74900 -120+62500=62380 -125+60000=59875 -150+50000=49850 -160+46875=46715 -200+37500=37300 -240+31250=31010 -250+30000=29750 -300+25000=24700 -375+20000=19625 -400+18750=18350 -480+15625=15145 -500+15000=14500 -600+12500=11900 -625+12000=11375 -750+10000=9250 -800+9375=8575 -1000+7500=6500 -1200+6250=5050 -1250+6000=4750 -1500+5000=3500 -1875+4000=2125 -2000+3750=1750 -2400+3125=725 -2500+3000=500
Calculate the sum for each pair.
a=-2500 b=3000
The solution is the pair that gives sum 500.
\left(x^{2}-2500x\right)+\left(3000x-7500000\right)
Rewrite x^{2}+500x-7500000 as \left(x^{2}-2500x\right)+\left(3000x-7500000\right).
x\left(x-2500\right)+3000\left(x-2500\right)
Factor out x in the first and 3000 in the second group.
\left(x-2500\right)\left(x+3000\right)
Factor out common term x-2500 by using distributive property.
x=2500 x=-3000
To find equation solutions, solve x-2500=0 and x+3000=0.
60000\left(-500\right)+x\times 2000=-4xx
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by x.
60000\left(-500\right)+x\times 2000=-4x^{2}
Multiply x and x to get x^{2}.
-30000000+x\times 2000=-4x^{2}
Multiply 60000 and -500 to get -30000000.
-30000000+x\times 2000+4x^{2}=0
Add 4x^{2} to both sides.
4x^{2}+2000x-30000000=0
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.
x=\frac{-2000±\sqrt{2000^{2}-4\times 4\left(-30000000\right)}}{2\times 4}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 4 for a, 2000 for b, and -30000000 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-2000±\sqrt{4000000-4\times 4\left(-30000000\right)}}{2\times 4}
Square 2000.
x=\frac{-2000±\sqrt{4000000-16\left(-30000000\right)}}{2\times 4}
Multiply -4 times 4.
x=\frac{-2000±\sqrt{4000000+480000000}}{2\times 4}
Multiply -16 times -30000000.
x=\frac{-2000±\sqrt{484000000}}{2\times 4}
Add 4000000 to 480000000.
x=\frac{-2000±22000}{2\times 4}
Take the square root of 484000000.
x=\frac{-2000±22000}{8}
Multiply 2 times 4.
x=\frac{20000}{8}
Now solve the equation x=\frac{-2000±22000}{8} when ± is plus. Add -2000 to 22000.
x=2500
Divide 20000 by 8.
x=-\frac{24000}{8}
Now solve the equation x=\frac{-2000±22000}{8} when ± is minus. Subtract 22000 from -2000.
x=-3000
Divide -24000 by 8.
x=2500 x=-3000
The equation is now solved.
60000\left(-500\right)+x\times 2000=-4xx
Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by x.
60000\left(-500\right)+x\times 2000=-4x^{2}
Multiply x and x to get x^{2}.
-30000000+x\times 2000=-4x^{2}
Multiply 60000 and -500 to get -30000000.
-30000000+x\times 2000+4x^{2}=0
Add 4x^{2} to both sides.
x\times 2000+4x^{2}=30000000
Add 30000000 to both sides. Anything plus zero gives itself.
4x^{2}+2000x=30000000
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.
\frac{4x^{2}+2000x}{4}=\frac{30000000}{4}
Divide both sides by 4.
x^{2}+\frac{2000}{4}x=\frac{30000000}{4}
Dividing by 4 undoes the multiplication by 4.
x^{2}+500x=\frac{30000000}{4}
Divide 2000 by 4.
x^{2}+500x=7500000
Divide 30000000 by 4.
x^{2}+500x+250^{2}=7500000+250^{2}
Divide 500, the coefficient of the x term, by 2 to get 250. Then add the square of 250 to both sides of the equation. This step makes the left hand side of the equation a perfect square.
x^{2}+500x+62500=7500000+62500
Square 250.
x^{2}+500x+62500=7562500
Add 7500000 to 62500.
\left(x+250\right)^{2}=7562500
Factor x^{2}+500x+62500. 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+250\right)^{2}}=\sqrt{7562500}
Take the square root of both sides of the equation.
x+250=2750 x+250=-2750
Simplify.
x=2500 x=-3000
Subtract 250 from both sides of the equation.
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