Question

What is the Value of x?

Answer 1

`\text{It's an isosceles triangle. Therefore}\ m\angle C=m\angle A:\\\\9y-3=69\qquad\text{add 3 to both sides}\\\\9y=72\qquad\text{divide both sides by 9}\\\\\boxed{y=8}\\\\\text{We know: The sum of the measures of the angles of a triangle is 180}^o.\\\\\text{Therefore we have the equation:}\\\\m\angle A+m\angle B+m\angle C=180^o\\\\\text{Substitute}\ m\angle A=m\angle C=69^o:\\\\69+(5x+2)+69=180\\\\138+5x+2=180\\\\140+5x=180\qquad\text{subtract 140 from both sides}\\\\5x=40\qquad\text{divide both sides by 5}\\\\\boxed{x=8}`

`Answer:\ \boxed{\boxed{x=8}}`

Answer 2

x=8

Explanation:

Since this is an isosceles triangle <A is equal to <C

<A = <C = 69

<A+ <B +<C = 180 because the 3 angles of a triangle add to 180 degrees.

69 + 5x+2 + 69 = 180

Combine like terms

140+ 5x = 180

Subtract 140 from each side

140-140 +5x =180-140

5x = 40

Divide by 5

5x/5 =40/5

x=8