Answer:
x = 18
Step-by-step explanation:
Since the triangles are similar then the ratios of corresponding sides are equal, that is
[tex]\frac{x+x+3}{x+3}[/tex] = [tex]\frac{14+12}{14}[/tex]
[tex]\frac{2x+3}{x+3}[/tex] = [tex]\frac{26}{14}[/tex] ( cross- multiply )
14(2x+3) = 26(x + 3) ← distribute both sides
28x + 42 = 26x + 78 ( subtract 26x from both sides )
2x + 42 = 78 ( subtract 42 from both sides )
2x = 36 ( divide both sides by 2 )
x = 18
