Considerando 2 conjuntos não vazios A e B, com A = {1,3,5,7,9,71} e B = {3, 6, 9, 12), determinando o número de elementos do conjunto A-B, encontramos:
A3
OB) 4
O C) 5
OD) 6​

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.

i suppose it should be (y=2x-5)

step-by-step explanation:

b and c are the correct answers.

good luck on the quiz! : d