1. x = 22, 2. x = 1, 3. x = 10
1.
2x - 28 = 16 ( add 28 to both sides )
2x = 44 ( divide both sides by 2 )
x = 22 ← solution
2.
12 = 5x + 7 ( subtract 7 from both sides )
5 = 5x ( divide both sides by 5 )
1 = x ⇒ x = 1 ← solution
3.
140 = 10x + 4x ( collect like terms on right side )
140 = 14x ( divide both sides by 14 )
10 = x ⇒ x = 10 ← solution