Toán a, |3x + 5| = |x – 7| b, |2x + 2| = |x – 7| 05/07/2021 By Quinn a, |3x + 5| = |x – 7| b, |2x + 2| = |x – 7|
a,$ |3x + 5| = |x – 7| $$⇔ 3x + 5 = x – 7 $$⇔ 3x – x = -7 – 5 $$⇔ 2x = -12$$⇔ x = -6$ b, $|2x + 2| = |x – 7|$$⇔ 2x + 2 = x – 7$$⇔ 2x – x = -7-2$$⇔ x = -9$ Trả lời
a, |3x + 5| = |x – 7| TH1: 3x – 5 = x – 7 2x = -2 x = -1 TH2: 3x – 5 = -(x-7) 3x – 5 = -x + 7 4x = 12 x = 3 b, |2x + 2| = |x – 7| TH1: 2x + 2 = x – 7 x = -9 TH2: 2x + 2 = -(x-7) 2x + 2 = -x + 7 3x = 5 x = `\frac{5}{3}` Trả lời
a,$ |3x + 5| = |x – 7| $
$⇔ 3x + 5 = x – 7 $
$⇔ 3x – x = -7 – 5 $
$⇔ 2x = -12$
$⇔ x = -6$
b, $|2x + 2| = |x – 7|$
$⇔ 2x + 2 = x – 7$
$⇔ 2x – x = -7-2$
$⇔ x = -9$
a, |3x + 5| = |x – 7|
TH1:
3x – 5 = x – 7
2x = -2
x = -1
TH2:
3x – 5 = -(x-7)
3x – 5 = -x + 7
4x = 12
x = 3
b, |2x + 2| = |x – 7|
TH1:
2x + 2 = x – 7
x = -9
TH2:
2x + 2 = -(x-7)
2x + 2 = -x + 7
3x = 5
x = `\frac{5}{3}`