The answer is x=13
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Ask me for the work!
Answer : 49
I hope you understand sorry for the ugly writing
If vertex angle is 42, and the base angles are congruent, this is an isosceles triangle, they each measure: 180-42/2. They each measure 69 degrees. The length of sides don't matter.
The solution will be where the graph crosses the x-axis.
When a graph crosses the x-axis, the value of the function is 0. Just look at your graph and look at the x-values where the graph crosses the x-axis.