Answer:
x=17
Step-by-step explanation:
well the triangles are congruent so that equation has to equal 61, so set it equal to 61, once you do that subtract 10 with 61 giving you 51, then divide 3 with 51 and you get 17
[tex]3x + 10 = 61 \\ 3x = 51 \\ x = 17[/tex]