Answer:
x = 15
Step-by-step explanation:
Corresponding sides have the same ratio:
UV/PR = TV/QR
(x +6)/14 = (x -3)/8
4(x +6) = 7(x -3) . . . . . . multiply by 56
4x +24 = 7x -21 . . . . . . eliminate parentheses
45 = 3x . . . . . . . . . . . add 21-4x
15 = x . . . . . . . . . . . .divide by 3
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Alternate solution
The long-side : short-side ratios for the two triangles are ...
14 : 8 = (x +6) : (x -3)
If we look at the differences between the ratio numbers we see ...
14 -8 = 6
(x +6) -(x -3) = 9
That is, the numbers in the second ratio must be 9/6 = 3/2 times the numbers in the first ratio. In other words, ...
x -3 = (3/2)(8) = 12
x = 15
Check: x +6 = 3/2(14) ; 15 +6 = 21
