There are two parts to this question.
part 1: Solve for x
part 2: what is the length of AB
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AB = BD is given. Therefore,
7x + 10 = 9x-2
10 + 2 = 9x - 7x
12 = 2x
x = 2
Now, Put the value of x in value of AB
AB = 7x + 10
AB = 7 × 2 + 10
AB = 14 + 10
AB = 24