Answer:
5
Step-by-step explanation:
Use the Exterior Angle Theorem.
The E.A.T states that the measurement of an exterior angle is found by adding the two opposite and non-adjacent interior angles.
In this case, the Exterior Angle is 121. The sum can be found by combining 17x - 4 and 8x. Set the equation:
17x - 4 + 8x = 121
First, combine like terms:
17x + 8x - 4 = 121
(17x + 8x) - 4 = 121
(25x) - 4 = 121
Next, Isolate the variable, x. Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS.
First, add 4 to both sides of the equation:
25x - 4 (+4) = 121 (+4)
25x = 121 + 4
25x = 125
Next, divide 25 from both sides:
(25x)/25 = (125)/25
x = 125/25
x = 5
5 is your value for x.
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