15-5(x+4)= -12-3
<=> 15-5x+20=-15
<=> 5x+20=15+15
<=> 5x+20=30
<=> 5x=30-20
<=> 5x=10
<=> x=10:5
<=> x=2.
15 - 5(x + 4) = -12 - 3
⇔ 15 - 5x - 20 = -15
⇔ -5x - 5 = -15
⇔ -5x = -15 + 5
⇔ -5x = -10
⇔ x = \(\dfrac{-10}{-5}\)
⇔ x = 2
Vậy x = 2
15-5(x+4) = -12 - 3
15-5(x+4) = -15
5(x+4) = 15-(-15)
5(x+4) = 30
x+4 = 30:5
x+4 = 6
x = 6-4
x = 2