Answer:
x = 9
Step-by-step explanation:
MN is a midline segment and is half the length of GH, thus
GH = 2 × MN, substitute values
15x - 45 = 10x ( subtract 10x from both sides )
5x - 45 = 0 ( add 45 to both sides )
5x = 45 ( divide both sides by 5 )
x = 9