[tex]\begin{gathered} \frac{5}{x+\text{ 4}}\text{ = }\frac{8}{x+10} \\ By\text{ cross multiplying we have.} \\ 5(x+10)\text{ = 8(}x\text{+10)} \\ 5x\text{ + 50 = 8}x\text{ + 80} \\ 5x-8x\text{ = 80 -50} \\ -3x\text{ = 30} \\ x\text{ =}\frac{30}{-3}\text{ = -10} \end{gathered}[/tex]