tolong bantu jawab pr mtk

(5*2)+(6*5)+(7*X)+(8*4)+(9*3)+(10*1)
/2 + 5 + X + 4 + 3 + 1
= 7,2

109 + 7X / 15 + X = 7,2

109 + 7X = 7,2 (15 + X)

109 + 7X = 108 + 7,2X

109 - 108 = 7,2X - 7X

1 = 0,2X

1 / 0.2 = X

5 = X

semoga membantu..