Verified answer

Resposta:

Explicação passo a passo:

na 5:

completar a paralela na esquerda."

"40+68+x =180"

108+x= 180"

"x = 180-108"

x = 72°

_________

6)

"5/8 = x/4"

"5/2= x/1" "

"5=2x "

"x = 5/2"

"x =2,5 *<=============

"5/8= 2,75/y"

"5Y = 22 "

" y = 22/5 "

*** y = 4,4 ***

___________

7)

"5/13= x/(45-x) "

" 5.(45-x)= 13x "

" 225-5x= 13x "

" 225 = 18.x"

* X=12,50 *

"5/13= (45-y)/y"

5y = 13.(45-y)

5y = 585-13y

"18y = 585"

" y = 32,50 *****

"y-x"

" = 32,5 - 12,5 "

" = 20"

______

8)

3x/6=2/(x+3)

x/2=2/(x+3)

x.(x+3) = 4"

"x²+3x-4= 0 "

"∆= b²-4 ac " ******

"∆=3²-4.1.(-4)"

"∆= 25"

"x = (-b +/- √∆)/2a "

"X = (-3+/-5)/2"

x ' = 1 *

"y = 3x+6"

y = 3.1+6"

"y =9"

*** *******