Answer:
Step-by-step explanation:
In similar triangles, the corresponding sides are in same proportion.
[tex]\sf \dfrac{4x}{3x+1}=\dfrac{15}{12}[/tex]
Cross multiply,
4x*12 = 15*(3x + 1)
48x = 15*3x + 15*1
48x = 45x + 15
48x -45x = 15
3x = 15
x = 15/3
x = 5
