X x 13 = 39
X = 39 : 13
X = 3
( x - 15 ) - 75 = 0
x - 15 = 0 + 75
x - 15 = 75
x = 75 + 15
x = 90
6x - 39 = 201
6x = 201 + 39
6x = 240
x = 40
X x 13 = 39
X = 39 : 13
X = 3
( x - 15 ) - 75 = 0
x - 15 = 0 + 75
x - 15 = 75
x = 75 + 15
x = 90
6x - 39 = 201
6x = 201 + 39
6x = 240
x = 240 : 6
x = 40
575 - ( 6x +70 ) = 445
6x + 70 = 575 - 445
6x + 70 = 130
6x = 130 - 70
6x = 60
x = 60 : 6
x = 10
X x 13 = 39
X = 39 : 13
X = 3
( x - 15 ) - 75 = 0
x - 15 = 75
x = 75 - 15
x = 50
6x - 39 = 201
6x = 162
x = 162 : 6
x = 27
575 - ( 6x +70 ) = 445
6x + 70 = 575 - 445
6x + 70 = 130
6x = 60
x = 10