Question

as raízes da equação
me ajudem por favor ​

Answer 1

Resposta:

1. Δ=b²-4.a.c

Δ=9²-4.9.2

Δ=81-72

Δ=9

X=-b±√Δ/2.a

X=-9±√9/2.9

x₁=$\frac{-9+3}{18}$

x₁=$\frac{-6}{18}$

x₁=$\frac{-1}{3}$

x₂=$\frac{-9-3}{18}$

x₂=$\frac{-12}{18}$

x₂=$\frac{-2}{3}$       C

2. d) x²-38x-480=0

(-48)²+38.(-48)-480=0

2304-1824-480=0

2304-2304=0

0=0

10²+38.10-480=0

100+380-480=0

480-480=0

0=0

3. d=$\frac{1}{2}$.g.t²

78,4=$\frac{1}{2}$.9,8.t²

9,8.t²=156,8

t²=$\frac{156,8}{9,8}$

t²=16

t=√16

t=4 s

4.

2x+(x+1)²=166

2x+(x+1).(x+1)=166

2x+x²+x+x+1=166

x²+4x+1=166

x²+4x+1-166=0

x²+4x-165=0

Δ=b²-4ac

Δ=4²-4.1.(-165)

Δ=16+660

Δ=676

X=-b±√Δ/2a

x=-4±√676/2.1  

x=-4±26/2

x'=$\frac{-4+26}{2}$=$\frac{22}{2}$=11          x"=$\frac{-4-26}{2}$=$\frac{-30}{2}$=-15      Resposta=11

5. x²+3x-10=x²-5x+6

x²-x²+3x+5x-10-6=0

8x-16=0

8x=16

x=$\frac{16}{8}$

x=2