e) \(\sqrt{4-\sqrt{7}}-\sqrt{4+\sqrt{7}}+\sqrt{2}\)

\(=\dfrac{\sqrt{8-2\sqrt{7}}}{\sqrt{2}}-\dfrac{\sqrt{8+2\sqrt{7}}}{\sqrt{2}}+\sqrt{2}\)

\(=\dfrac{\sqrt{\left(\sqrt{7}-1\right)^2}}{\sqrt{2}}-\dfrac{\sqrt{\left(\sqrt{7}+1\right)^2}}{\sqrt{2}}+\sqrt{2}\)

\(=\dfrac{1}{\sqrt{2}}\left(\sqrt{7}-1-\sqrt{7}-1\right)+\sqrt{2}\)

\(=-\sqrt{2}+\sqrt{2}=0\)

\(=y^4+y^3-y^2-2y-\left(y^4+y^3+y^2-2y^2-2y-2\right)\)

\(=y^4+y^3-y^2-2y-y^4-y^3+y^2+2y+2=2\)

\(=3\left(x^2-2xy+y^2-4z^2\right)\)

\(=3\left(x-y-2z\right)\left(x-y+2z\right)\)

= 3(x² - 2xy + y² - 4z²)

= 3((x - y)² - 4z²)

= 3(x - y - 2z)(x - y + 2z)

0,54

5400m2=0,54ha

e: =6+10=16

f: =15-25=-10

g: =-3-7=-10

h: =-9-11+20=0

i: \(=18+29+158-18-29=158\)

307dm=30m7dm

307dm = 30,7 m

307dm = 307dm

tích đúng cho tớ được không

x=3y=2z

nên x/6=y/2=z/3

Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:

\(\dfrac{x}{6}=\dfrac{y}{2}=\dfrac{z}{3}=\dfrac{2x-3y+4z}{2\cdot6-3\cdot2+4\cdot3}=\dfrac{54}{18}=3\)

Do đó: x=18; y=6; z=9

thank bn nka

1: \(=\left(3x-2\right)\left(y+7\right)\)

b: \(=-x\left(x-y\right)-3\left(x-y\right)\)

\(=\left(x-y\right)\left(-x-3\right)\)

c: \(=\left(x-3y\right)^2\)

\(1,=\left(3x-2\right)\left(7+y\right)\\ 2,=x\left(y-x\right)+3\left(y-x\right)\\ =\left(x+3\right)\left(y-x\right)\\ c,=\left(x-3y\right)^2\)