4x2-21x-18=0

Simple and best practice solution for 4x2-21x-18=0 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 4x2-21x-18=0 equation:



4x^2-21x-18=0
a = 4; b = -21; c = -18;
Δ = b2-4ac
Δ = -212-4·4·(-18)
Δ = 729
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{729}=27$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-21)-27}{2*4}=\frac{-6}{8} =-3/4 $
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21)+27}{2*4}=\frac{48}{8} =6 $

See similar equations:

| 5/6x-1/9x=102 | | -1x+-10=-4x+-4 | | 16-2x=+4 | | (×+4)(x-4)=9 | | (b-7)/7=8 | | (a-6)/2=6 | | 15x+6=14x+2 | | (a+17)/10=5 | | 22°+45°=x | | 6x+1=13x+-12 | | (e+7)/4=7 | | n~7-6=14 | | 7(x-8)=77 | | 7(q−8)=77 | | f=20000+20000(.05)(2) | | -1=6+v-6 | | 6(l-4)=42 | | x(4.15)x=1.4 | | −12w^2−2=11w | | -8y+33=3y | | 6(l−4)=42 | | 2(p+8)=50 | | 4+9n=24 | | r/4-6=2 | | X=8x+310x-7 | | 57=3r | | 9/m+16=17 | | 3k+(-15)=-16 | | n÷3+5=7 | | 5x-6=-3x+18 | | 14h-8=104 | | 14h−8=104 |

Equations solver categories