Answer:
∠ABE = 145°
Step-by-step explanation:
because angle CBA and ABE form a straight line, we know that they must add together to 180 degrees
and because DBE and ABE <em>also</em> form a straight line/angle, they must add together to 180 degrees
we can set this up as a system of equations (I will be writing ABE as "y")
2x + 21 + y = 180
5x + y = 180
We can combine this to beL
2x + 21 + y = 5x + y
- 2x -2x
21 + y = 3x + y
- y - y
21 = 3x
x = 7
If we plug this back into our original equations (which is set to 180 degrees), we can find y
2(7) + 21 + y = 180
14 + 21 + y = 180
35 + y = 180
- 35 - 35
y = 145
(remember, "y" is angle ABE)
we can check this value (ABE = 145) by substituting our second equation
5(x) + ABE = 180
35 + 145 = 180
180 = 180
(TRUE)
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so, the measure of ∠ ABE is 145°
hope this helps!!