Answer:
∠A = 6x + 4
Explanation:
Hello There!
We are given the exterior angle ∠ACD and an interior angle ∠B
If you didn't know this is the rule for exterior angles of a triangle:
An exterior angle is equal to the sum of its opposite interior angles
so ∠ACD = ∠A + ∠B ( ∠A and ∠B being the opposite interior angles)
So with the information that we are given we plug them into their corresponding angle
then we would have
8x+5 = ∠A + 2x + 1
now we solve for A
Well how do we solve for A?
Well we have to isolate the variable
To do so we want to get rid of 2x + 1
We do that by subtract each side by 2x and 1
8x + 5 - (2x + 1 ) = 6x + 4
we're left with
∠A = 6x + 4