If it's not what You are looking for type in the equation solver your own equation and let us solve it.
5d^2+21d+9=0
a = 5; b = 21; c = +9;
Δ = b2-4ac
Δ = 212-4·5·9
Δ = 261
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$
The end solution:
$\sqrt{\Delta}=\sqrt{261}=\sqrt{9*29}=\sqrt{9}*\sqrt{29}=3\sqrt{29}$$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-3\sqrt{29}}{2*5}=\frac{-21-3\sqrt{29}}{10} $$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+3\sqrt{29}}{2*5}=\frac{-21+3\sqrt{29}}{10} $
| 7+y/5=-13 | | 2x-2=25-x^2 | | √(2x-2)=5-x | | √(2x-2)=5x-x | | 2x+30×29x=300 | | (-13+5y)+y=5 | | 7^x=145 | | (2b+7)+b=196 | | 3x+37=4x+21 | | -6+r/8=-8 | | | | 4x^2-76x=0 | | 7(-3-2m)=-7(m-1) | | 10x2+35x=(2x+7) | | -1/2=a/12 | | -15-x=2 | | 2(x+5+x)=58 | | 3/2h+4.1=9.8 | | 50+10x0=7=2= | | p+24=20 | | 10+x=-21 | | 3/2h+4.1=4.8 | | -22-n=-5 | | G(X)=3x²-4x-3. | | k-(-25)=7 | | 2x-18;x=4 | | 8x-10=6x-18 | | k+(-16)=3 | | k+23=20 | | {t}^{2}-64=0 | | 10x+2+13x-6=90 | | -0.02p-0.02(4-6p)=0.06(p-3)-0.3 |