gente pelo amor de Deus preciso muito da ajuda de voocs :( ',

calcule essas equações de 2 grau :

1° x²+3x-10=0

2° x²+2x+1=0

3° x²+6x-7=0

4° x²-2x-8=0

5° 2x²-9x+4=0

6° x²-2x=x+4

7° 25x²-10x+1=0

8°x²+10=9x-10

9° x²-2x-15=0

10° (x+2)²+x=0

1

Respostas

2014-03-27T14:49:59-03:00
1)x²+3x-10=0
a=1 b=3 c=-10
delta=b²-4.a.c
delta=3²-4.1.(-10)
delta=9-4.(-10)
delta=9+40
delta=49

 \frac{-b+- \sqrt{delta}}{2.a}

 \frac{-3+- \sqrt{4} }{2.1}

 \frac{-3+-7}{2}

x'= \frac{-3+7}{2} =  \frac{4}{2} :2=  \frac{2}{1}

x''= \frac{-3-7}{2}=  \frac{-10}{2}

2)x²+2x+1=0
a=1 b=2 c=1
delta=b²-4.a.c
delta=2²-4.1.1
delta=4-4
delta=0

 \frac{-b+- \sqrt{delta} }{2.a}

 \frac{-2+- \sqrt{0} }{2.1}

 \frac{-2}{2} :2= 1


3) x²+6x-7=0
a=1 b=6 c=-7
delta=b²-4.a.c
delta=6²-4.1.(-7)
delta=36-4.(-7)
delta=36-11
delta=25

 \frac{-b+- \sqrt{delta} }{2.a}  =  \frac{-6+- \sqrt{25} }{2.1}

 \frac{-6+-5}{2}

x'= \frac{-6-5}{2} =  \frac{-11}{2}

x''= \frac{-6+5}{2} =  \frac{-1}{2}

4) x²-2x-8=0
a=1 b=-2 c=-8
delta=b²-4.a.c
delta=(-2)²-4.1.(-8)
delta=4-4.(-8)
delta=4-(-32)
delta=4+32=36

 \frac{-b+- \sqrt{delta} }{2.1} =  \frac{-(-2)+- \sqrt{36} }{2}

 \frac{2+-6}{2}

x'= \frac{2+6}{2} =  \frac{8}{2} :2 = \frac{4}{1}

x''= \frac{2-6}{2}= \frac{-4}{2}

5) 2x²-9x+4=0
a=2 b=-9 c=4
delta=b²-4.a.c
delta=(-9)²-4.2.4
delta=81-32
delta=49

 \frac{-b+- \sqrt{delta} }{2.a} =  \frac{-(-2)+- \sqrt{49} }{2.2}

 \frac{2+-7}{4}

x'=  \frac{2+7}{4}= \frac{9}{4}
x'' \frac{2-7}{4} =  \frac{-5}{4}