Toán Tính: -15+(89+15-72)-(89-72) Tìm x biết -|-8|-3(x-1)=7 07/12/2021 By Remi Tính: -15+(89+15-72)-(89-72) Tìm x biết -|-8|-3(x-1)=7
-15+(89+15-72)-(89-72) = -15 + 89 +15 – 72 – 89 +72 = (15 – 15 )+ ( 72-72) + (89 – 89) = 0 -|-8|-3(x-1)=7 = -8 – 3(x-1) = 7 = 3(x-1)= (-8)- 7 = 3(x-1)= – 15 = x-1 = (-15) : 3 = x- 1= -5 ⇒ x= (-5) + (-1)= -6 Đáp án: a, 0 b, -6 Trả lời
$-15+(89+15-72)-(89-72)$ $=$ $-15 + 89 + 15 – 72 -89 + 72$ $=$ $(-15+15)+(89-89)+(-72+72)$ $= 0$ $-|-8|-3(x-1)=7$ $⇔ -8 – 3x + 3 = 7$ $⇔ 3x+3 = -15 $ $⇔ 3x = -18$ $⇔ x = -6$ Vậy $x=-6$ Trả lời
-15+(89+15-72)-(89-72)
= -15 + 89 +15 – 72 – 89 +72
= (15 – 15 )+ ( 72-72) + (89 – 89)
= 0
-|-8|-3(x-1)=7
= -8 – 3(x-1) = 7
= 3(x-1)= (-8)- 7
= 3(x-1)= – 15
= x-1 = (-15) : 3
= x- 1= -5
⇒ x= (-5) + (-1)= -6
Đáp án:
a, 0
b, -6
$-15+(89+15-72)-(89-72)$
$=$ $-15 + 89 + 15 – 72 -89 + 72$
$=$ $(-15+15)+(89-89)+(-72+72)$
$= 0$
$-|-8|-3(x-1)=7$
$⇔ -8 – 3x + 3 = 7$
$⇔ 3x+3 = -15 $
$⇔ 3x = -18$
$⇔ x = -6$
Vậy $x=-6$