0.4x - 0.8(x - 4) = 1.3x - 1.9
0.4(3) - 0.8(3 - 4) = 1.3(3) - 1.9
1.2 + 0.8 = 3.9 - 1.9
2 = 2 ---------------------------------> TRUE
1/4 x + 7 = 31/4
1/4(3) + 28/4 = 31/4
3/4 + 28/4 = 31/4
31/4 = 31/4 ---------------------------------> TRUE
x - 2(x + 4) = x + 2
3 - 2(3 + 4) = 3 + 2
3 - 2(7) = 5
3 - 14 = 5
-11 = 5 ---------------------------------FALSE
1/2 x - 4 = 2
1/2(3) - 4 = 2
3/2 - 8/2 = 2
-5/2 = 2---------------------------------FALSE
3(x + 4) - x = 18
3(3 + 4) - 3 = 18
3(7) - 3 = 18
21 - 3 = 18
18 = 18 ---------------------------------TRUE
Answer
0.4x - 0.8(x - 4) = 1.3x - 1.9
1/4 x + 7 = 31/4
3(x + 4) - x = 18