Question

calcule mentalmente as raizes de cada equacao.a)x''-13x 42=0 b)x''-11x 28=0 c)x"-2x 1=0 d)x"-3x-10=0

Answer 1

a)x''-13x 42=0
d = (-13)^2 -4.1.42
d = 169 - 168
d= 1
x'=13+1 / 2 = 7
x"=13-1/2 = 66

b)x''-11x +28=0
d=(-11)^2 - 4.1.28
d= 121 - 112
d= 9
x'=11+3/2=7
x"=11-3/2 = 4

c)x"-2x+1=0
d=(-2)^2-4.1.1
d= 4 -4 = 0
x'=2+0/2 = 1
x"=2-0/2=1

d)x"-3x-10=0
d=(-3)^2-4.1.-10
d= 9 +40 = 49
x'=3+7/2 = 5
x"=3-7/2=-2