Answer: x ≥ -3/5
Step-by-step explanation:
The mistake:
dividing by (x+2/5)
At the left side of the inequality we have a factor ( x + 2/5 ) and you can divide, but to keep the inequality you have to do the same at the right hand side of the inequality and x+ 2/5 are two terms. You can pass x + 2/5 to the right shanging their sign as follow
5*(x+2/5) -x -2/5 ≥ 0 ⇒ 5x + 2 - x -2/5 ≥ 0
4x + 2 + 2/5 ≥0 ⇒ 4x + 12/5 ≥ 0 ⇒ ( 20x + 12)/5 ≥ 0
20x + 12 ≥0 ⇒20x ≥-12 x ≥ - (12/20) or x ≥ -3/5
