If a line segment ab is on the number line, and the point a is at - 3 and point b is at 7, the length of ab is

The length of AB is 10.

Step-by-step explanation:

The length of AB would be the distance between A and B. This can be found by subtracting A from B (B from A would also work), and then taking the absolute value of what we get. In other words:

L = |B - A|          where L is the length of AB.

We know that A = -3 and B = 7, so now we just have to plug in A and B into the equation L = |B - A|  and solve for L (the length of AB).

L = |B - A|

Plug in -3 and 7 for A and B, respectively

L = |7 - (-3)|

Remember: a - (-b) = a + b

L = |7 + 3|

Simplify.

L = |10|

The absolute value of 10 is 10.

L = 10.

The length of AB is 10.

I hope you find this helpful. Feel free to ask me questions if the do not understand anything in my answer. Happy studying. :)

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.