Toán a, -7.3x-5+2.7x-14=28 b, 10|4x-8|+20=180 c, x mũ 2+x=0 12/07/2021 By Maria a, -7.3x-5+2.7x-14=28 b, 10|4x-8|+20=180 c, x mũ 2+x=0
a, -7.3x-5+2.7x-14= 28 ⇔ 7x.( -3+2)-19= 28 ⇔ -7x= 47 ⇔ x= $\frac{-47}{7}$ b, 10.| 4x-8|+20= 180 ⇔ 10.| 4x-8|= 160 ⇔ | 4x-8|= 16 ⇔ \(\left[ \begin{array}{l}4x-8=16\\4x-8=-16\end{array} \right.\) ⇔ \(\left[ \begin{array}{l}x=6\\x=-3\end{array} \right.\) c, x²+x= 0 ⇔ x.( x+1)= 0 ⇔ x= 0 hpặc x= -1 Trả lời
a, -7.3x-5+2.7x-14=28 => -21x – 5 + 14x – 14 = 28 => -21x + 14x = 28 + 14 + 5 => -7x = 47 => x = $\frac{-47}{7}$ Vậy x = $\frac{-47}{7}$ b, 10|4x-8|+20=180 => 10.|4x-8| = 160 => |4x-8| = 16 => \(\left[ \begin{array}{l}4x-8=16\\4x-8=-16\end{array} \right.\) => \(\left[ \begin{array}{l}x=6\\x=-2\end{array} \right.\) Vậy x = 6 hoặc x = -2 c, $x^{2}$ + x = 0 => x.(x+1) = 0 => \(\left[ \begin{array}{l}x=0\\x+1=0\end{array} \right.\) => \(\left[ \begin{array}{l}x=0\\x=-1\end{array} \right.\) Vậy x = 0 hoặc x = -1 Trả lời
a, -7.3x-5+2.7x-14= 28
⇔ 7x.( -3+2)-19= 28
⇔ -7x= 47
⇔ x= $\frac{-47}{7}$
b, 10.| 4x-8|+20= 180
⇔ 10.| 4x-8|= 160
⇔ | 4x-8|= 16
⇔ \(\left[ \begin{array}{l}4x-8=16\\4x-8=-16\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=6\\x=-3\end{array} \right.\)
c, x²+x= 0
⇔ x.( x+1)= 0
⇔ x= 0
hpặc x= -1
a, -7.3x-5+2.7x-14=28
=> -21x – 5 + 14x – 14 = 28
=> -21x + 14x = 28 + 14 + 5
=> -7x = 47
=> x = $\frac{-47}{7}$
Vậy x = $\frac{-47}{7}$
b, 10|4x-8|+20=180
=> 10.|4x-8| = 160
=> |4x-8| = 16
=> \(\left[ \begin{array}{l}4x-8=16\\4x-8=-16\end{array} \right.\)
=> \(\left[ \begin{array}{l}x=6\\x=-2\end{array} \right.\)
Vậy x = 6 hoặc x = -2
c, $x^{2}$ + x = 0
=> x.(x+1) = 0
=> \(\left[ \begin{array}{l}x=0\\x+1=0\end{array} \right.\)
=> \(\left[ \begin{array}{l}x=0\\x=-1\end{array} \right.\)
Vậy x = 0 hoặc x = -1