B: rút gọn
a) Ta có: \(\left(x-2\right)\left(x^2+2x+4\right)-6x^2+12x\)
\(=x^3-6x^2+12x-8\)
\(=\left(x-2\right)^3\)
b) Ta có: \(\left(2x+5\right)\left(5-2x\right)+\left(x-5\right)\left(4x+5\right)\)
\(=25-4x^2+4x^2+5x-20x-25\)
=-15x
Tính:
\(a)\left(-2x^2\right)\cdot\left(3x-4x^3+7-x^2\right)\)
\(b)\left(x+3\right)\cdot\left(2x^2-3x-5\right)\)
\(c)\left(-6x^5+7x^4-6x^3\right):3x^3\)
\(d)\left(9x^2-4\right):\left(3x+2\right)\)
\(e)\left(2x^4-13x^3+15x^2+11x-3\right):\left(x^2-4x-3\right)\)
\(A\left(x\right)=-4x^5-x^3+4x^2+5x+9+4x^5-6x^2-2\)
\(B\left(x\right)=-3x^4-2x^3+10x^2-8x+5x^3-7-2x^3+8x\)
thu gọn đa thúc rồi sắp xếp theo thứ tự giảm dần của biến
tính A(x) + B(x) và A(x) - B(x)
Bài `1`: Rút gọn các biểu thức sau:
\(a)4x^2\left(5x^2+3\right)-6x\left(3x^3-2x+1\right)-5x^3\left(2x-1\right)\)
\(b)\dfrac{3}{2}x\left(x^2-\dfrac{2}{3}x+2\right)-\dfrac{5}{3}x^2\left(x+\dfrac{6}{5}\right)\)
Bài `2`: Thực hiện các phép nhân sau:
\(a)\left(x^2-x\right)\cdot\left(2x^2-x-10\right)\)
\(b)\left(0,2x^2-3x\right)\cdot5\left(x^2-7x+3\right)\)
\(c)6x^2\cdot\left(2x^3-3x^2+5x-4\right)\)
\(d)\left(-1,2x^2\right)\cdot\left(2,5x^4-2x^3+x^2-1,5\right)\)
Tìm x:
\(\frac{2x-3}{\left(7-6x\right)^2}+\frac{x-2}{\left(7-6x\right)^2}=\frac{6x-3}{\left(3x-5\right)^2}-\frac{12x-10}{\left(3x-5\right)^2}\)
Tìm x biết
1) \(\left(2x+3\right)\left(x-4\right)+\left(x-5\right)\left(x-2\right)=\left(3x-5\right)\left(x-4\right)\)
2)\(\left(8x-3\right)\left(3x+2\right)-\left(4x+7\right)\left(x+4\right)=\left(2x+1\right)\left(5x+1\right)-33\)
3)\(6x\left(3x+5\right)-2x\left(9x-2\right)+\left(17-x\right)\left(x-1\right)+x\left(x-18\right)-17x^2=0\)
4)\(\left(x-1\right)\left(x+2\right)-\left(x-3\right)+5x-7=0\)
Giúp mình nha. Camon nhiều
Bài 1 :Rút gọn
\(\left(4x^2-3y\right)a2y-\left(3x^2-4y\right)3y\)
\(4x^2\left(5x-3y\right)-x^2\left(4x+y\right)\)
\(2ax^2-a\left(1+2x^2\right)-\left\{a-x\left(x+a\right)\right\}\)
Bài 2:Tìm x
a)\(2x\left(x+1\right)-x^2\left(x+2\right)+x^3-x+1=0\)
b)\(4x\left(3x+2\right)-6x\left(2x+5\right)+21\left(x-1\right)=0\)
Bài 3:Rút gọn
\(x\left(1+x+x^2+...+x^9\right)-\left(1+x+x^2+...+x^9\right)\)
Tìm nghiệm đa thức sau:
\(a.B\left(x\right)=\left(x+\frac{1}{2}\right).\left(x-3\right)\\ b.D\left(x\right)=x^2-x\\ c.E\left(x^3+8\right)\\ d.F\left(x\right)=2x-5+\left(x-17\right)\)
\(e.C\left(x\right)=x^2-9\\ f.A\left(x\right)=x^2-4x\\ g.H\left(x\right)=\left(2x+4\right).\left(7-14x\right)\)
\(h.G\left(x\right)=\left(3x-5\right)-\left(18-6x\right)\)
Rút gọn các biểu thức :
a, \(\left(3x+5\right)^2+\left(3x-5\right)^2-\left(3x+2\right)\left(3x-2\right)\)
b, \(2x\left(2x-1\right)^2-3x\left(x+3\right)\left(x-3\right)-4x\left(x+1\right)^2\)
\(c,\left(x+y-z\right)^2+2\left(z-x-y\right)\left(x+y\right)+\left(x+y\right)^2\)
a)∣∣x2+∣∣6x−2||=x2+4
b)\(\left|2x+3\right|-2\left|4-x\right|=5\)
c)\(\left|x+3\right|+\left|x+1\right|=3x\)
