1 câu trả lời
Đáp án:
`|2x+1|≥3`
`⇔2x−1≥±(3)`
`TH1:`
`2x−1≥3`
`2x≥3+1`
`2x≥4`
`(2x)/2≥4/2`
`⇔x≥4/2`
`⇒x≥2`
`TH2:`
`2x−1≥−3`
`2x≥−3+1`
`2x≥−2`
`(2x)/2≥(−2)/2`
`⇔x≥(−2)/2`
`⇒x≥−1`
`⇒x ∈ {2;−1}`
Đáp án:
`|2x+1|≥3`
`⇔2x−1≥±(3)`
`TH1:`
`2x−1≥3`
`2x≥3+1`
`2x≥4`
`(2x)/2≥4/2`
`⇔x≥4/2`
`⇒x≥2`
`TH2:`
`2x−1≥−3`
`2x≥−3+1`
`2x≥−2`
`(2x)/2≥(−2)/2`
`⇔x≥(−2)/2`
`⇒x≥−1`
`⇒x ∈ {2;−1}`