tìm x biết 2x – 3 = 0 5 ( 7x + 5 ) + 15 = 0 7 ( 3x + 4 ) – 10 = 4 15 – 2 ( 7x – 3 ) = 11 13/07/2021 Bởi Vivian tìm x biết 2x – 3 = 0 5 ( 7x + 5 ) + 15 = 0 7 ( 3x + 4 ) – 10 = 4 15 – 2 ( 7x – 3 ) = 11
1/ $2x – 3 = 0$ $2x=3$ $x=$ $\dfrac{3}{2}$ Vậy $x=$ $\dfrac{3}{2}$ 2/ $5. ( 7x + 5 ) + 15 = 0$ $35x+25+15=0$ $35x+40=0$ $35x=0-40$ $35x=-40$ $x=$ $\dfrac{-8}{7}$ Vậy $x=$ $\dfrac{-8}{7}$ 3/ $7 .( 3x + 4 ) – 10 = 4$ $21x+28-10-4=0$ $21x=-14$ $x=$ $\dfrac{-2}{3}$ Vậy $x=$ $\dfrac{-2}{3}$ 4/ $15 – 2 .( 7x – 3 ) = 11$ $15-14x+6-11=0$ $-14x+10=0$ $x=$ $\dfrac{5}{7}$ Vậy $x=$ $\dfrac{5}{7}$ Bình luận
1/ $2x – 3 = 0$
$2x=3$
$x=$ $\dfrac{3}{2}$
Vậy $x=$ $\dfrac{3}{2}$
2/ $5. ( 7x + 5 ) + 15 = 0$
$35x+25+15=0$
$35x+40=0$
$35x=0-40$
$35x=-40$
$x=$ $\dfrac{-8}{7}$
Vậy $x=$ $\dfrac{-8}{7}$
3/ $7 .( 3x + 4 ) – 10 = 4$
$21x+28-10-4=0$
$21x=-14$
$x=$ $\dfrac{-2}{3}$
Vậy $x=$ $\dfrac{-2}{3}$
4/ $15 – 2 .( 7x – 3 ) = 11$
$15-14x+6-11=0$
$-14x+10=0$
$x=$ $\dfrac{5}{7}$
Vậy $x=$ $\dfrac{5}{7}$
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