b)  63 y 3 7 y với y > 0

=  63 y 3 7 y = 9 y 2 = 3 y = 3 y do y > 0

a) \(\sqrt{128\left(x-y\right)^2}\)

\(=\sqrt{8^2\cdot2\left(x-y\right)^2}\)

\(=\left|8\left(x-y\right)\right|\sqrt{2}\)

\(=8\left|\left(x-y\right)\right|\sqrt{2}\)

b) \(\sqrt{150\left(4x^2-4x+1\right)}\)

\(=\sqrt{5^2\cdot6\left(2x-1\right)^2}\)

\(=\left|5\left(2x-1\right)\right|\sqrt{6}\)

\(=5\left|2x-1\right|\sqrt{6}\)

c) \(\sqrt{x^3-6x^2+12x-8}\)

\(=\sqrt{\left(x-2\right)^3}\)

\(=\sqrt{\left(x-2\right)^2\left(x-2\right)}\)

\(=\left|x-2\right|\sqrt{x-2}\)

a: \(=\sqrt{64\cdot2\cdot\left(x-y\right)^2}=8\sqrt{2}\cdot\left|x-y\right|\)

b; \(=\sqrt{25\cdot6\left(2x-1\right)^2}=5\sqrt{6}\cdot\left|2x-1\right|\)

c: \(=\sqrt{\left(x-2\right)^3}=\left|x-2\right|\cdot\sqrt{x-2}\)

\(\sqrt{\left(-9\right)\cdot\left(-36\right)\cdot ab^2}\)

\(=\sqrt{9\cdot36\cdot ab^2}\)

\(=3\cdot4\cdot\left|b\right|\cdot\sqrt{a}\)

\(=12\left|b\right|\cdot\sqrt{a}\)

Sửa đề: Đưa thừa số vào trong dấu căn

a: \(3\sqrt{x^2}=\sqrt{3^2\cdot x^2}=\sqrt{9x^2}\)

b: \(-5\sqrt{y^4}=-\sqrt{5^2\cdot y^4}=-\sqrt{25y^4}\)

c: \(3\sqrt{5x}=\sqrt{3^2\cdot5x}=\sqrt{45x}\)

d: \(x\sqrt{7}=\sqrt{x^2\cdot7}=\sqrt{7x^2}\)

√(28a4b2 ) = √((2a2b)2.7) = √7 |2a2b| = 2√7a2b (do b ≥ 0)

25 x 3 = 25 x 2 . x = 5 x x = 5 x x ( với x > 0 )

7 x 2 = x 7 = x 7 ( với x > 0 )

chịu.-.

HT~~~

a, -2x^2y căn 7 

b, ab^2 căn 63 

c, a-1 căn 147a-147

d, y+2 nhân căn [192 nhân (y+2)^3]

a)-2x²y√7

b) 3ab²√7

c) 7(a-1)√3(a-1)

d) 8(y+2)²√3(y+2)