$2x+5=9$

1

？ --

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$2x=9-5$

2

$2x=4$

3

$x=\frac{4}{2}$

4

$x=2$

$3(3-2x)=5(7-5x)$

1

Because by expanding, we
distribute the terms and remove the parentheses
, which usually allows us to simplify the expression further.
$9-6x=35-25x$

2

$-6x=35-25x-9$

3

$-6x=-25x+26$

4

，我們需要這個只在一邊

$-6x+25x=26$

5

$19x=26$

6

$x=\frac{26}{19}$

$6x=12$

1

$x=\frac{12}{6}$

2

$x=2$

$\sqrt{x+4}=x+5$

1

$x+4={x}^{2}+10x+25$

2

$x+4-{x}^{2}-10x-25=0$

3

$-9x-21-{x}^{2}=0$

4

$x=\frac{9+\sqrt{3}\imath }{-2},\frac{9-\sqrt{3}\imath }{-2}$

5

$x=-\frac{9+\sqrt{3}\imath }{2},-\frac{9-\sqrt{3}\imath }{2}$

${x}^{4}+9{x}^{3}+9{x}^{2}-85x-150$

1

$({x}^{3}+7{x}^{2}-5x-75)(x+2)$

2

$({x}^{2}+10x+25)(x-3)(x+2)$

3

Because $${a}^{2}+2ab+{b}^{2}$$ is a common expression with a known factored form. This allows us to factor the expression in the next step.
$({x}^{2}+2(x)(5)+{5}^{2})(x-3)(x+2)$

4

${(x+5)}^{2}(x-3)(x+2)$

${w}^{2}+8w-65$

1

$$-5$$和$$13$$

2

$(w-5)(w+13)$