\(a.\sqrt{\left(\sqrt{2}-\sqrt{3}\right)^2}+\sqrt{18}=\left|\sqrt{2}-\sqrt{3}\right|+3\sqrt{2}=\sqrt{3}-\sqrt{2}+3\sqrt{2}\left(\sqrt{3}>\sqrt{2}\right)=\sqrt{3}+2\sqrt{2}\)\(b.3\sqrt{2}-4\sqrt{18}+2\sqrt{32}-\sqrt{50}=3\sqrt{2}-12\sqrt{2}+8\sqrt{2}-5\sqrt{2}=-6\sqrt{2}\)

Lời giải:

$10+2.4^2=10+2.16=10+32=42$

Đáp án A

$50-4.3^2=50-4.9=50-36=14$

Đáp án A.

a: \(=\sqrt{3}-\sqrt{2}+3\sqrt{2}=2\sqrt{2}+\sqrt{3}\)

\(\left(x^3+3x^2-ax+b\right):\left(x^2-2\right)\\ =\left(x^3-2x+3x^2-6+2x-ax+b+6\right):\left(x^2-2\right)\\ =\left[x\left(x^2-2\right)+3\left(x^2-2\right)+x\left(2-a\right)+\left(b+6\right)\right]:\left(x^2-2\right)\\ =x+3\left(\text{dư }x\left(2-a\right)+\left(b+6\right)\right)\)

Để phép chia hết thì \(\left\{{}\begin{matrix}2-a=0\\b+6=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=2\\b=-6\end{matrix}\right.\)

a)

\(3x\left(x^2+6x+2\right)\)

\(=3x.x^2+3x.6x+3x.2\)

\(=3x^3+18x^2+6x\)

b)

\(\left(x-3\right)\left(x^2+6x+8\right)\)

\(=x\left(x^2+6x+8\right)-3\left(x^2+6x+8\right)\)

\(=x^3+6x^2+8x-3x^2-18x-24\)

\(=x^3+3x^2-10x-24\)

a) 4x²(x² - 5x + 2)

= 4x².x² - 4x².5x + 4x².2

= 4x⁴ - 20x³ + 8x²

b) (2x²  - 5x + 3) : (2x - 3)

= (2x² - 3x - 2x + 3) : (2x - 3)

= [(2x² - 3x) - (2x - 3)] : (2x - 3)

= [x(2x - 3) - (2x - 3)] : (2x - 3)

= (2x - 3)(x - 1) : (2x - 3)

= x - 1

a, \(4x^2\left(x^2-5x+2\right)\\ =4x^4-20x^3+8x^2\)

b, \(\left(2x^2-5x+3\right):\left(2x-3\right)\\ =x-1\)

a: \(=x^2-1-x^2-x+6=-x+5\)

A=x^4+3x^3-5x^2+7

B=x^2+4x^2+2x+1=5x^2+2x+1

A-B=x^4+3x^3-5x^2+7-5x^2-2x-1

=x^4+3x^3-10x^2-2x+6