Lời giải:
Sử dụng công thức $(a-1)(a+1)=a^2-1$ ta có:
$8F=(9-1)(9+1)(9^2+1)(9^4+1)(9^8+1)...(9^{32}+1)$
$=(9^2-1)(9^2+1)(9^4+1)(9^8+1)...(9^{32}+1)$
$=(9^4-1)(9^4+1)(9^8+1)...(9^{32}+1)$
$=(9^8-1)(9^8+1)...(9^{32}+1)$
$=(9^{16}-1)...(9^{32}+1)=(9^{32}-1)(9^{32}+1)=9^{64}-1$
$\Rightarrow F=\frac{9^{64}-1}{8}$
Tính giá trị các biểu thức sau:
D= \(4x^2-2x+3x\left(x-5\right)\)tại \(x=-1\)
E= \(x^{10}-2020x^9+2020x^8-2020x^7+...+2020x^2-2020x\) tại \(x=2019\)
F= \(x^{10}+20x^9+20x^8+...+20x^2+20x\) tại \(x=19\)
Mấy bạn giúp mk vs ai nhanh mk sẽ vote ạ các bạn làm đầy đủ cho mk nha mk cảm ơn nhìu :33
9^8.2^8-(18^4-1)(18^4+1)
tính nhanh
a) A=\(2018^2-2017\cdot2019\)
b) B=\(9^8\cdot2^8-\left(18^4-1\right)\cdot\left(18^4+1\right)\)
c) C=\(163^2+74\cdot163+37^2\)
d) D=\(\dfrac{2018^3-1}{2018^2+2019}\)
e) E=\(\left(2+1\right)\cdot\left(2^2+1\right)\cdot\left(2^4+1\right)\cdot\left(2^8+1\right)\cdot\left(2^{16}+1\right)-2^{32}\)
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
1. Tìm x:
3(2x-1)(3x-1) - (2x-3)(9x-1) = 0
2(5x-8) - 3(4x-5) = 4(3x-4) +10
(3x+2)(2x+9) - (x+2)(6x+1)
VD: 3(2x-1) = 3 nhân (2 nhân x trừ 1)
2. Chứng minh: (x+9)(x+b) = x^2 + (a+b)x + ab
pls help :(
Chứng minh rằng:
a) \(A=x^2-x^9-x^{1945}⋮B=x^2-x+1\)
b) \(C=8x^9-9x^8+1⋮D=\left(x-1\right)^2\)
Bài 1: Áp dụng những hằng đẳng thức để tìm x
a) -(x+3)(x-4)+(x+1)(x-1)=10
b) (2x-1)(x-2)-(x+3)(2x-7)=3
c) (x-5)(4-x)-(x-1)(x+3)=-2x
d) 3(x+7)(x-7)-(x-1)(3x+2)=13
e) 5(x-3)(x-7)-(5x+1)(x-2)=8
f) (3x-4)(x-2)=3x(x-9)-10
g) 5x(x-3)=(x-2)(5x-1)-5
h) 6(x-3)(x-4)-6x(x-2)=4
i) (x-2)(x+3)-(x+4)(x-7)=5-x
k) (4x-5)(x+1)-4(x-1)(x+1)=7
l) (3x-4)(x-2)=3x(x-9)-3
Tìm x:
a, (x-3).(x-1)=(x-3)\(^2\)
b, (4\(x^2\)-9)=0
c, x\(^2\)+6x+9=0
Mong m.n giúp
a) x2(x - 5) + 5 - x = 0; b) 3x4 - 9x3 = -9x2 + 27x;
c) x2(x + 8) + x2 = -8x; d) (x + 3)(x2 -3x + 5) = x2 + 3x.
e) 3x(x - 1) + x - 1 = 0;
f) (x - 2)(x2 + 2x + 7) + 2(x2 - 4) - 5(x - 2) = 0;
g) (2x - 1)2 - 25 = 0;
h) x3 + 27 + (x + 3)(x - 9) = 0.
i)8x3 - 50x = 0; k) 2(x + 3)-x2 - 3x = 0;
m)6x2 - 15x - (2x - 5)(2x + 5) =