\(4\left(3x-2\right)+\left(2-3x\right)^3\)
\(=\left(2-3x\right)^3-4\left(2-3x\right)\)
\(=\left(2-3x\right)\left[\left(2-3x\right)^2-4\right]\)
\(=\left(-3x+2\right)\left(-3x+2-2\right)\left(-3x+2+2\right)\)
\(=-3x\cdot\left(-3x+2\right)\left(-3x+4\right)\)
3x^2(x^3-3x^2+1)
=3x^2.x^3+3x^2.(-3x^)+3x^2.1
=3x^5-9x^4+3x^2
mấy bạn ơi sao ra 3x^5-9x^4 vậy chỉ mk với mình cần gấp ạ
Rút gọn các biểu thức sau:
a,(3x+1)^2-2(3x+1)(3x-5)+(3x-5)^2
b,(3x^2-y)^2
c,(3x+5)^2+(3x-5)^2-(3x+2)(3x-2)
d,2x(2x-1)^2-3x(x+3)(Õ-3)-4x(x+1)^2
e,(x-2)(x^2+2x+4)-(x+1)^2+3(x-1)(x+1)
f,(x^4-5x^2+25)(x^2+5)-(2+x^2)^2+3(1+x^2)^2
(3x^2-16x) ÷ (-3x) +x(x-4) =-2 (5x^3+20x^2-25x) ÷25x=(x-1) (x+2) (3x+1) ^3=3x+1 x^2-4x+4=9(x-2) Tìm x
Bài 2: (2 điểm) Tìm x, biết:
a) (3x + 4)2 – (3x – 1)(3x + 1) = 49
b) x2 – 4x + 4 = 9(x – 2)
c) x2 – 25 = 3x - 15
d) (x – 1)3 + 3(x + 1)2 = (x2 – 2x + 4)(x + 2)
Tìm x :( bài 14 trang 11 sách bồi dưỡng năng lực tự học toán 8)
Câu 2 : (2x+3)2+(x-1)*(x+1)=5*(x+2)2-(x-5)*(x+1)+(x+4)2
Câu 3 : (-x+5)*(x-2)+(x-7)*(x+7)=(3x+1)2-(C)*(3x+2)
Câu 4 : (5x-1)*(x+1)-2(x-3)2=(x+2)*(3x-1)-(x+4)2+(x2-x)
Câu 5 : (4x-1)2-(3x+2)*(3x-2)=(7x-1)*(x+2)+(2x+1)2-(3x+2)
Câu 6 : (2x+3)2-(5x-4)*(5x+4)=(x+5)2-(3x-1)*(7x+2)-(x2-1+1)
Câu 7 : (1-3x)2-(x-2)*(9x+1)=(3x-4)*(3x+4)-9(x+3)2
Câu 8 : (3x+4)*(3x-4)-(2x+5)=(x-5)+(2x+1)2-(x2-2x)+(x-1)2
Câu 9 : (x-7)*(x+1)-(x-3)2=(3x-5)*(3x+5)-(3x+1)+(x-2)2-x2
Câu 10 : -5(x+3)2+(x-1)*(x+1)+(2x-3)=(5x-2)2-5x(5x+3)
d) (3x – 5)(7 – 5x) – (5x + 2)(2 – 3x) = 4 g) 3(2x - 1)(3x - 1) - (2x - 3)(9x - 1) =0 j) (2x – 1)(3x + 1) – (4 – 3x)(3 – 2x) = 3 k) (2x + 1)(x + 3) – (x – 5)(7 + 2x) = 8 m) 2(3x – 1)(2x + 5) – 6(2x – 1)(x + 2) = - 6
BÀI 6 :rút gọn phân thức
\(\dfrac{x^3+3x^3+3x+1}{x^2+x}\)
b)\(\dfrac{x^3-3x^2+3x-1}{2x-2}\)
c)\(\dfrac{x^2+4x+4}{2x+4}\)
d)\(\dfrac{(x-1)(-x-2)}{x+2}\)
e)\(\dfrac{x^2-y^2}{x+y}\)
f)\(\dfrac{3x^2+4xy^2}{6x+8y}\)
g)\(\dfrac{-3x^2-6x}{4-x^2}\)
BÀI 7 :quy đồng mẫu thức các phân thức
\(\dfrac{2}{5x^3y^2}và \dfrac{3}{4xy}\)
b)\(\dfrac{x}{x^2-2xy+y^2} và \dfrac{x}{x^2-xy}\)
c)\(\dfrac{1}{x+2};\dfrac{2}{2x+4}và \dfrac{3}{3x+6}\)
d)\(\dfrac{1}{x+3};\dfrac{2}{2x-6}và \dfrac{3}{3x-9}\)
1: 3/x+1 + 2/x+2 = 5x+4/x2+ 3x + 2
2: 2/3x + 1 - 15/6x2-x-1 = 3/2x - 1
3: 9/3x - 1 - 5-x/3x2-4x+1 = 4/x+ 1
4:5/x - 2 + 2/x+4 = 3x/x2 + 2x - 8
5: 4/x+6 + 1/x - 3 = 9/x2 + 3x - 18
6:x/x-3 - 2x2 +9/2x2 - 3x - 9= 1/2x + 3
1) 4(2x-3)^2-9(4x^2-9)^2
2) a^6-a^4+2a^3+2a^2
3)(3x^2+3x+2)^2-(3x^2+3x-2)^2
phân tích thành nhân tử
1)3x^2-9 2)1/2x^2-2y^2 3)3x^2-12y^2 4)1/3x^2y^2-3x^2
