Question

A) x²+12x+36=-9
b) 4x²-4x+1=9
c) 4x²-36x+81=16

Answer 1

a)
x²+12x+36=-9
x²+12x+45=0
Δ=144-180=-36
√-36 não existe raiz
S={ }

b)
4x²-4x+1=9
4x²-4x-8=0  (: por 4)
x²-x-2=0
Δ=1+8=9
√Δ=3
$x'= \frac{1+3}{2} = \frac{4}{2} =2$

$x"= \frac{1-3}{2} = \frac{-2}{2} =-1$

S={-1,2}

c)
4x²-36x+81=16
4x²-36x+65=0
Δ=1296-1040=256
√Δ=16


$x'= \frac{36+16}{8} = \frac{52}{8} = \frac{13}{8}$

$x"= \frac{36-16}{8} = \frac{20}{8} = \frac{5}{2}$

S={$\frac{5}{2} , \frac{13}{2}$}