I need help with solving for x. Then find the measure of the base angle. Please

x = 8

base angle = 81 deg

Step-by-step explanation:

we observe that because the given triangle is a isosceles triangle, the base angles must be the same.

Hence the missing base angle must also be (10x+1)°

recall that all internal angles of an triangle must add up to 180 deg,

hence

180° = sum of all internal angles

180° = 18° + (10x+1)° + (10x+1)°

180° = 18° + 2(10x+1)°    (subtracting 18 from both sides)

180 - 18 = 2(10x+1)

162 = 2(10x+1)   dividing both sides by 2)

162 / 2 = 10x + 1

81 = 10x + 1    (subtracting 1 from both sides)

81 - 1 = 10x

10x = 80   (divide both sides by 10)

x = 80/10

x = 8   (answer)

substituting x = 8 into the expression for the base angle

base angle = (10x+1)

= 10(8) + 1

= 10 + 1

= 81