Giải:
a) \(47.53\)
\(=\left(50-3\right).\left(50+3\right)\)
\(=50^2-3^2\)
\(=2500-9\)
\(=2491\)
Vậy ...
b) \(9^8.2^8-\left(18^4-1\right)\left(18^4+1\right)\)
\(=\left(9.2\right)^8-\left[\left(18^4\right)^2-1^2\right]\)
\(=18^8-\left(18^8-1\right)\)
\(=18^8-18^8+1\)
\(=1\)
Vậy ...
Bài 1: Tính nhanh:
a) \(127^2+146.127+73^2\)
b) \(9^8.2^8-\left(18^4-1\right)\left(18^4+1\right)\)
c) \(100^2-99^2+98^2-97^2+...+2^2-1\)
d) \(\dfrac{780^2-220^2}{125^2+150.125+75^2}\)
Bài 2 : So sánh:
a) \(A=\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)và \(B=2^{32}\)
b) \(C=\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)và \(D=3^{32}-1\)
* Tìm X
a/ ( x+2)2+ ( x-3)2 - 2(x-1)(1+x) = 9
b/ ( 3x - 1)2+ (3x+1)2- 18( x-2)(x+2) = 5
c/ ( 6x-5)2 - ( 6x +7)(6x-7) + 4( x-3) = 8
1 .CMR : (x+y)^3 -(x-y^3) = 2y.(3x^2 + y^2 )
2. tìm x :
a, (x-3)^3 - (x^3 -27) +9.(x+1)^2=18
b, x.(x-4).(x+4)-(x^3-125)=13
Viết các đa thức sau thành tích
1. ( 3x + 2)2 - 4
2. 4x2 - 25y2
3. 4x2- 49
4. 8z3 + 27
5. \(\dfrac{9}{25}\)x4 - \(\dfrac{1}{4}\)
6. x32 - 1
7. 4x2 + 4x + 1
8. x2 - 20x + 100
9. y4 -14y2 + 49
10. 125x3 - 64y3
Bài 1: cho x+y+z=0 và x^2+y^2+z^2=14 .Tính S=x^4+y^4+z^4
Bài 2: cho x>y>0 và a+b+c=0.Tính S= \(\dfrac{1}{a^2+b^2-c^2}\)+\(\dfrac{1}{b^2+c^2-a^2}\)+\(\dfrac{1}{c^2+a^2-b^2}\)
bài 3: cho a^2 +4b +4=0
b^2 +4c+4=0
c^2 +4a+4=0 .Tính S=a^18+b^18+c^18
a) Cho x+y=9,xy=18 tính x3+y3, x4+y4,x3-y3
b)Cho x+y = -9 ,tính A= x2+2xy+y2-6x-5y-5
tính nhanh (2+1)(22+1)(24+1)(28+1)
18^3-3.18^2.8+3.18.8^2-2
tinh nhanh nha mn
Tìm x:
a, (x-1)3+3(x+1)2=(x2-2x+4)(x+2)
b, x2-4=8(x-2)
c, x2-4x+4=9(x-2)
d, 4x2-12x+9=(5-x)2
