Answer:
![\boxed{11}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/2asvxnktoc08l26qcn9uslcm29me1vwrur.png)
Explanation:
The ratios of corresponding segments are the same, so you can write ...
(3x +7)/5 = 48/6
Multiplying by 5 gives ...
3x + 7 = 40
3x = 33 . . . . . . subtract 7
x = 11 . . . . . . . . divide by 3
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Please note that the value (3x+7) is missing units. If this is 3x+7 cm, then the value of x is 11 cm. If this is (3x+7) cm, then the value of x is 11 (no units).