7x^2+21x=3

Simple and best practice solution for 7x^2+21x=3 equation. Check how easy it is, and learn it for the future. Our solution is simple, and easy to understand, so don`t hesitate to use it as a solution of your homework.

If it's not what You are looking for type in the equation solver your own equation and let us solve it.

Solution for 7x^2+21x=3 equation:



7x^2+21x=3
We move all terms to the left:
7x^2+21x-(3)=0
a = 7; b = 21; c = -3;
Δ = b2-4ac
Δ = 212-4·7·(-3)
Δ = 525
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:
$\sqrt{\Delta}=\sqrt{525}=\sqrt{25*21}=\sqrt{25}*\sqrt{21}=5\sqrt{21}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-5\sqrt{21}}{2*7}=\frac{-21-5\sqrt{21}}{14} $
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+5\sqrt{21}}{2*7}=\frac{-21+5\sqrt{21}}{14} $

See similar equations:

| -5n+6=-6n+n | | 4c+3=3c+8 | | 18+2x=-6(7+3x) | | -5-4n=-5(n-2)-2n | | 2(4-c+2c)=12 | | 14-3n=6n-4 | | b+1=-b-13 | | -68=-4(2+3x) | | 6p+5(p-4)=-64 | | 205-3x=33x+17 | | -5+2a+1=-6 | | 18=p+5p | | -4=-k+5k | | 2(3w-5)=7w+2-3w | | 1.5+3.25=x | | 6d-27+5d=105 | | 2y+5+5y=3y+13 | | -2y+3=-4+8y-3 | | x-400=0.6x | | g÷9=4 | | 3(4-2x)=2x-2(3-2x) | | 25+x2=43 | | 4-2(2.x)=3+2(2-2x) | | -1(-5y+-1)=6 | | 8x-4-3x-6=10x-3 | | |y|+7=13 | | 42/x)+x=2x-1 | | 3x=2/33x-2 | | 6m+5=16+3m+6 | | 1000-x+720=0 | | 100-x+720=0 | | 5a+20=3a+6 |

Equations solver categories