HELP PLEASE ILL GIVE 10 POINTS

The answer would be 150 degrees.

Step-by-step explanation:

When looking at the problem you can see that you have two parallel lines and a transversal. Since the two lines are parallel, this allows alternate interior angles to form, i.e. <A and <B.

Since angle A and B are alternate interior angles, you can now set the two equal to each other.

So, in order to find out what x equals, you have to set the two equations equal to each other.

8x-10=3x+90

Next, solve the new equation.

8x-10=3x+90

Add 10 to both sides.

8x=3x+100

Subtract 3x from both sides.

5x=100

Divide both sides by 5 and you'll get your answer.

x=20

Now that you know what x equals, you can substitute it into the equation for B.

<B= 3(20)+90

60+90= 150

<B=150 degrees

That gives you your answer of <B = 150 degrees.

To check your work you can also substitute x into the equation for <A.

<A= 8(20)-10

160-10= 150

<A=150 degrees.

Therefore, you have just proved that the answer is 150 degrees.

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.