Answer
x=10
Work Step by Step
The lengths of $\overline{JH}$ and $\overline{HK}$ sum to the length of $\overline{JK}$
Segment Addition Postulate
$(4x-15)+(2x+3)=48$
combine like terms
$6x-12=48$
add 12 to each side
$6x-12+12=48+12$
$6x=60$
divide each side by 6
$6x\div6=60\div6$
$x=10$
