Question

Please, help !!!!!!!!​

Answer 1

from the figure above, we can say that △ABC ~ △DEC by "AA", so then we can say

`\cfrac{(x+7)+34}{34}=\cfrac{15+3x}{3x}\implies \cfrac{x+41}{34}=\cfrac{15+3x}{3x} \\\\\\ 3x^2+123x=510+102x\implies 3x^2+21x-510=0 \\\\\\ 3(x^2+7x-170)=0\implies x^2+7x-170=0 \implies (x-10)(x+17)=0 \\\\\\ x= \begin{cases} ~~ 10 ~~ \checkmark\\ -17 \end{cases}\hspace{5em}\stackrel{\textit{\LARGE AB}}{15+3(10)}\implies 45`