26.)
to figure out x, you need to write this equation:
5x + 12 = 7x - 8
it is equal because of Base Angle Theorem Converse. The triangle shown is an isosceles because of the tick marks on the sides
you should get x = 10 degrees
27.)
you can first substiute the x values in the expressions
5(10)+12 = 62
the other equation is also going to be 62 degrees because of base angle theorem converse too, but ill do it out anyway
7(10)-8 = 62
ok so to find angle A do:
180 - (62 * 2) = 180 - 124 = 56 degrees