Explicação passo-a-passo:
X²+7x=0
X(x+7)=0
X+7=0
X=0-7
X=-7
S=>{0 e -7}
-3x²+9x=0
3x²-9x=0(÷3)
X²-3x=0
X(x-3)=0
X-3=0
X=0+3
X=3
S=>{ 0 e 3}
2x²+3x=0
X(2x+3)=0
2x+3=0
2x=0-3
2x=-3
X=-3/2
S=>{ 0 e -3/2}
X²+50=0
X²=0-50
X²=-50
Não possui solução no campo dos números reais.
-5x²+20=0
5x²-20=0(÷5)
X²-4=0
X²=0+4
X²=4
X=±√4
X=±2
S=>{ 2 e -2}
X²-9x+20=0
A=1
B=-9
C=20
∆=b²-4ac
∆=(-9)²-4*1*20
∆=81-80
∆=1
-b±√∆/2a
9±√1/2*1
9±1/2
X¹=9+1/2=10/2=>5
X²=9-1/2=8/2=>4
X²+9x+20=0
A=1
B=9
C=20
∆=b²-4ac
∆=9²-4*1*20
∆=81-80
∆=1
-b±√∆/2a
-9±√1/2*1
-9±1/2
X¹=-9+1/2=-8/2=>-4
X²=-9-1/2=-10/2=>-5
X²-3x-10=0
A=1
B=-3
C=-10
∆=b²-4ac
∆=(-3)²-4*1*-10
∆=9+40
∆=49
-b±√∆/2a
3±√49/2*1
3±7/2
X¹=3+7/2=10/2=>5
X²=3-7/2=-4/2=>-2
2x²+7x+6=0
A=2
B=7
C=6
∆=7²-4*2*6
∆=49-48
∆=1
-b±√∆/2a
-7±√1/2*2
-7±1/4
X¹=-7+1/4=-6/4(÷2)=>-3/2
X²=-7-1/4=-8/4=>-2
-x²-x+20=0
A=-1
B=-1
C=20
∆=b²-4ac
∆=(-1)²-4*-1*20
∆=1+80
∆=81
-b±√∆/2a
1±√81/2*-1
1±9/-2
X¹=1+9/-2=10/-2=>-5
X²=1-9/-2=-8/-2=>4
