Question

encontre as raízes da equação ( valor de x ) das equações

a)₋x² ₊ 7x ₊30 =0 △=169
b)₋2²₊4x₊6=0 △=64
c)x² ₋3x₋4=0 △=25
OBS: tem que ter as contas

Answer 1

a)₋x² ₊ 7x ₊30 =0 △=169
a=-1
b=7
c=30
△=169
x = - b ± √Δ / 2a
x = - 7 ± √169 / 2.(-)1
x = - 7 ± 13 / -2
x'= -7+13/-2
x'=6/-2
x'=-3
x''=-7-13/-2
x''=-20/-2
x''=10
S{-3 ; 10}


b)₋2x²₊4x₊6=0
a=-2
b=4
c=6
△=64
x = - b ± √Δ / 2a
x = - 4 ± √64 / 2.(-2)
x = - 4 ± 8 / -4
x'=-4+8/-4
x'=4/-4
x'=-1
x''=-4-8/-4
x''=-12/-4
x''=3
S{-1 ; 3}

c)x² ₋3x₋4=0
a=1
b=-3
c=-4
△=25
x = - b ± √Δ / 2a
x = - (-3) ± √25 / 2.1
x = 3 ± 5 / 2
x'=3+5/2
x'=8/2
x'=4
x''=3-5/2
x''=-2/2
x''=-1
S{-1 ; 4}