Question

X ao quadrado menos 10x + 21=0

Answer 1

   x²-10x+21=0 usar bascara
Δ=b²-4ac ⇒ Δ=(-10)²-4.1.21⇒Δ=100-64=16
X= -b+/-√Δ/2a
X1= -b+√Δ/2a⇒X1=-(-10)+√16/2.1⇒X1=7
X2= -b-√Δ/2a⇒X2=-(-10)-√16/2.1⇒X2=3
Conjunto solução (7,3)

Answer 2

X²-10x+21=0

X= -b +/- √(b²-4ac)/2a

X= -(-10) +/- √((-10)²-4.1.21)/2.1

X= 10 +/- √(100-84)/2

X= 10 +/- √16 / 2

X= 10 +/- 4/2

X' = 10 +4/2 ⇒X' =14/2 ⇒ X' =7

X'' = 10 -4/2 ⇒X'' = 6/2 ⇒X'' = 3