x + 3/2 + x - 1 = 4/5
Collect the same terms
x + x + 3/2 - 1 = 4/5
2x + 3/2 - 2/2 = 4/5
2x + (3 - 2)/2 = 4/5
2x + 1/2 = 4/5
2x + 0.5 = 0.8
Subtract both sides 0.5
2x + 0.5 - 0.5 = 0.8 - 0.5
2x + 0 = 0.3
2x = 3/10
Divide both sides by 2
2x ÷ 2 = ( 3/10 ) ÷ 2
x = 3/10 × 1/2
x = 3/20
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Check :
3/20 + 3/2 + ( 3/20 - 1 ) = 4/5
3/20 + 30/20 + ( 3/20 - 20/20 ) = 4/5
(3 + 30)/20 + (3 - 20)/20 = 4/5
33/20 - 17/20 = 4/5
(33 - 17)/20 = 4/5
16/20 = 4/5
4 × 4 / 4 × 5 = 4/5
4/5 = 4/5
Thus we found the correct value of x .
And we're done...