Question

calcule as raízes das equações:
a)-m²-2m+3=0
b)2a²+15a+7=0​

Answer 1

Explicação passo-a-passo:

a)

-m²-2m+3=0

a=-1

b=-2

c=3

Δ=b²-4ac

Δ=(-2)²-4(-1)(3)

Δ=4+12

Δ=16

$m={-b\pm\sqrt{\Delta} \over2a}={-(-2)\pm\sqrt{16} \over2(-1)}={2\pm4\over-2}\\ \\ m'={2+4\over-2}={6\over-2}=-3\\ \\ m"={2-4\over-2}={-4\over-2}=2\\ \\ S=\{-3,2\}$

==========================b)

2a² +15a+7=0

a=2

b=15

c=7

Δ=b²-4ac

Δ=15²-4(2)(7)

Δ=225-56

Δ=169

$a={-b\pm\sqrt{\Delta}\over2a}=} {-15\pm\sqrt{169} \over2(2)}={-15\pm13\over4}\\ \\ a'={-15+13\over4}={2\over4}={1\over2}\\ \\ a"={-15-13\over4}=-{28\over4}=-7\\ \\ S=\{-7,{1\over2}\}$

Answer 2

basta usar a formula de bhaskara:

a)-m^2-2m+3=0

a=-1

b=-2

c=3

delta=b^2-4ac

-2^2-4.(-1).3

16

a=-b+- raiz de delta/2a

2+-4/-2

a1=-3

a2=1

b)2a²+15a+7=0

a=2

b=15

c=7

delta=225-56

169

a=-15+-13/4

a1=-1/2

a2=-7