tính ( rút gọn)
(x-10)^2 - 2(x-10)(5x-3)+(5x-3)^2
Tính (rút gọn )
(x-10)^2-2(x-10)(5x-3)+(5x+3)
(x-2)^3-x(x-3)^2
(x-2)(x^2+2x+4)-x(x+1)(x-1)
(x+3)(x^2-3x+9)-x(x^2-1)
BÀI 2: rút gọn biểu thức
a) 2x( 5-3x^2) - 10( 6+x)
b)3(-x+2)-6( 1-x+5x^20)
c) 7x( 2-5x^2+1/2x^3)- 14x( 1-2x^2)
a) \(2x\left(5-3x^2\right)-10\left(6+x\right)\)
\(=10x-6x^3-60-10x\)
\(=\) \(-6x^3-60\)
a) \(2x\left(5-3x^2\right)-10\left(6+x\right)\\ =2x.5-2x.3x^2-10.6-10.x\\ =10x-6x^3-60-10x\)
b) \(3\left(-x+2\right)-6\left(1-x+5x^{20}\right)\\ =-3.x+3.2-6.1+6.x-5.5x^{20}\\ =-3x+6-6+6x-25x^{20}=25x^{20}+3x\)
c) \(7x\left(2-5x^2+\dfrac{1}{2}x^3\right)-14x\left(1-2x^2\right)\\ =7x.2-7x.5x^2+7x.\dfrac{1}{2}x^3-14x.1+14x.2x^2\\ =14x-25x^3+\dfrac{7}{2}x^4-14x+28x^3=3x^2+\dfrac{7}{2}x^4\)
b) \(3\left(-x+2\right)-6\left(1-x+5x^{20}\right)\)
\(=-3x+6-6+6x-30x^{20}\)
\(=3x-30x^{20}\)
Rút gọn rồi tính A vs x =2
A=(7x−8).(7x+8)−10.(2x+3)^2+5x.(3x−2)^2−4x.(x−5)^2
rút gọn c
(x+2/x2-5x+x-2/x2+5x) chia x2+10/x2-25
rút gọn \(\dfrac{1}{x-3}+\dfrac{3x^2-8x+10}{x^2-5x+6}-\dfrac{2x-4}{x-2}\) giải chi tiết ạ
\(\dfrac{1}{x-3}+\dfrac{3x^2-8x+10}{x^2-5x+6}-\dfrac{2x-4}{x-2}\left(ĐK:x\ne3;x\ne2\right)\)
\(=\dfrac{1}{x-3}+\dfrac{3x^2-8x+10}{x\left(x-2\right)-3\left(x-2\right)}-\dfrac{2x-4}{x-2}\)
\(=\dfrac{1}{x-3}+\dfrac{3x^2-8x+10}{\left(x-3\right)\left(x-2\right)}-\dfrac{2x-4}{x-2}\)
\(=\dfrac{x-2}{\left(x-2\right)\left(x-3\right)}+\dfrac{3x^2-8x+10}{\left(x-3\right)\left(x-2\right)}-\dfrac{\left(2x-4\right)\left(x-3\right)}{\left(x-2\right)\left(x-3\right)}\)
\(=\dfrac{x-2+3x^2-8x+10-\left(2x^2-6x-4x+12\right)}{\left(x-2\right)\left(x-3\right)}\)
\(=\dfrac{3x^2-7x+8-2x^2+10x-12}{\left(x-2\right)\left(x-3\right)}\)
\(=\dfrac{x^2+3x-4}{\left(x-2\right)\left(x-3\right)}\)
\(=\dfrac{x^2+3x-4}{x^2-5x+6}\)
\(A=\left(\dfrac{2}{\sqrt{x}-2}+\dfrac{3}{2\sqrt{x}+1}-\dfrac{5\sqrt{x}}{2x-3\sqrt{x}-2}\right):\dfrac{2\sqrt{x}+3}{5x-10\sqrt{x}}\)
rút gọn
\(A=\dfrac{4\sqrt{x}+2+3\sqrt{x}-6-5\sqrt{x}}{\left(\sqrt{x}-2\right)\left(2\sqrt{x}+1\right)}\cdot\dfrac{5x\left(\sqrt{x}-2\right)}{2\sqrt{x}+3}\left(x>0;x\ne4\right)\\ A=\dfrac{2\left(\sqrt{x}-2\right)}{\left(\sqrt{x}-2\right)\left(2\sqrt{x}+1\right)}\cdot\dfrac{5x\left(\sqrt{x}-2\right)}{2\sqrt{x}+3}\\ A=\dfrac{10x\left(\sqrt{x}-2\right)}{\left(2\sqrt{x}+1\right)\left(2\sqrt{x}+3\right)}\)
\(A=\left(\dfrac{2}{\sqrt{x}-2}+\dfrac{3}{2\sqrt{x}+1}-\dfrac{5\sqrt{x}}{2x-3\sqrt{x}-2}\right):\dfrac{2\sqrt{x}+3}{5x-10\sqrt{x}}\)
\(=\dfrac{4\sqrt{x}+2+3\sqrt{x}-6-5\sqrt{x}}{\left(\sqrt{x}-2\right)\left(2\sqrt{x}+1\right)}\cdot\dfrac{5\sqrt{x}\left(\sqrt{x}-2\right)}{2\sqrt{x}+3}\)
\(=\dfrac{2\sqrt{x}-4}{\left(2\sqrt{x}+1\right)}\cdot\dfrac{5\sqrt{x}}{2\sqrt{x}+3}\)
Rút gọn:
a. .2x2 + 3(x-1)(x+1) - 5x(x+1)
b. (8-5x)(x+2)+4(x-2)(x+1)+2(x-2)(x+2)+10
c. 4(x-1)(x+5)-(x+2)(x+5)-3(x-1)(x+2)
a. \(2x^2+3\left(x-1\right)\left(x+1\right)-5x\left(x+1\right)\)
\(=2x^2+3\left(x^2-1\right)-5x^2-5x\)
\(=2x^2+3x^2-3-5x^2-5x\)
\(=\left(2x^2+3x^2-5x^2\right)-5x-3\)
\(=-5x-3\)
b,c mk ms học lớp 7
rút gọn biểu thức
\(\left(\frac{5x+2}{x^2-10}+\frac{5x-2}{x^2+10}\right)\cdot\frac{x^2-100}{x^2+4}\)
Cho P=x-2/x+2 × (5x+10/7x-14 + x-2/3x-6) + 3(x^2-4)/2(x-2)^2
a) Tìm đkxđ
b) Rút gọn