What's (negative 7) plus (positive 7) plus (negative 17) (adding positive and negative numbers)

The answer is -17

The negative 7 and positive 7 add up to 0. They are opposites which cancel out. Think of it like being 7 dollars in debt (negative 7) and that debt is fully canceled out by the positive amount of money (positive 7). Put another way, the negative 7 means you go down 7 while the positive 7 means you go up 7.

After the first two terms cancel to 0, the -17 is the only thing left. Adding 0 to any number keeps that number the same.

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.