Question

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Answer 1

a: x+5=9

hay x=4

b: -3x=24

nên x=-8

Answer 2

Câu 2:

a.

$x+5=-2+11=9$

$x=9-5=4$

b.

$-3x=-5+29=24$

$x=24:(-3)=-8$

c.

$|x|-9=-2+17=15$

$|x|=15+9=24$

$\Rightarrow x=\pm 24$

d.

$|x-9|=-2+17=15$

$\Rightarrow x-9=15$ hoặc $x-9=-15$

$\Leftrightarrow x=24$ hoặc $x=-6$

Answer 3

Câu 3:

$4x=|x+19|+|x+5|+|x+2021|\geq 0$

$\Rightarrow x\geq 0$

$\Rightarrow x+19>0; x+5>0; x+2021>0$. Khi đó:

$|x+19|+|x+5|+|x+2021|=4x$

$x+19+x+5+x+2021=4x$
$3x+2045=4x$

$x=2045$ (tm)