3X + X3 = 11 x 11
tìm x biết:3x + x3 = 11 x 11
dấu x ở giữa 2 số 11 là dấu nhân
3x+x3=121 =>x{3+3}=121 =>x9=121 =>sai
đề sai
\(3x+3x=11\cdot11\)
\(6x=121\)
\(x=\frac{121}{6}\)
X3 + 3X = 11 x 11
vậy X bằng bao nhiêu ?
trả lời hộ mk nha nhớ ghi cách lam vào nhé
rút gọn A,B,C
A=(3x+7)(2x+3)-(3x-5)(2x+11)
B=(x2-2)(x2+x-1)-x(x3+x2-3x-2)
C=x(x3+x2-3x-2)-(x2-2)(x2+x-1)
\(A=6x^2+23x+21-\left(6x^2+23x-55\right)=76\\ B=x^4+x^3-x^2-2x^2-2x+2-x^4-x^3+3x^2+2x\\ =2\\ C=x^4+x^3-3x^2-2x-\left(x^4+x^3-x^2-2x^2-2x+2\right)\\ =-2\)
Tìm x,biết:
3x + x3 = 11 x 11
3x + x3 = 11 x 11
3x + x3 = 121
Mà 121 = 38 + 83
Vậy x = 8
x = 8
vì 11 x 11 = 121
mà 1 = 8 + 3 nên x = 8
quý vị khán giả thấy đúng thì k nhá
3x + x3 = 11x11
3x + x3 = 121
Ta đặt phép tính như sau:
3x + x3 = 121 (cái này bạn đặt tính dọc nhé!)
- NX : Hàng đơn vị : x + 3 = 1 => x+3 có nhớ => x = 8
Vậy x =8
Thế thôi, k nhé?
cu the thay vao la tinh duoc
chk hoc tot
Tìm x biết
3x + x3 = 11 x 11
3x + x3 = 11 x 11
=> 30 + x + x.10 + 3 = 121
=> 33 + x.11 = 121
=> x.11 = 121 - 33 = 88
=> x = 88 : 11 = 8
Thực hiện phép tính
1/x+2 + 5/2x2+3x-2
-3x2/x3+11 + 1/x2-x+1 +1/x+1
1/1-x +1/1+x +2/1+x2 +4/1+x4
a) \(\dfrac{1}{x+2}+\dfrac{5}{2x^2+3x-2}\)
\(=\dfrac{1}{x+2}+\dfrac{5}{2x^2+4x-x-2}\)
\(=\dfrac{2x-1}{\left(2x-1\right)\left(x+2\right)}+\dfrac{5}{2x\left(x+2\right)-\left(x+2\right)}\)
\(=\dfrac{2x-1+5}{\left(2x-1\right)\left(x+2\right)}\)
\(=\dfrac{2x+4}{\left(2x-1\right)\left(x+2\right)}\)
\(=\dfrac{2\left(x+2\right)}{\left(2x-1\right)\left(x+2\right)}\)
\(=\dfrac{2}{2x-1}\)
\(---\)
b) \(\dfrac{-3x^2}{x^3+1}+\dfrac{1}{x^2-x+1}+\dfrac{1}{x+1}\) (sửa đề)
\(=\dfrac{-3x^2}{\left(x+1\right)\left(x^2-x+1\right)}+\dfrac{x+1}{\left(x+1\right)\left(x^2-x+1\right)}+\dfrac{x^2-x+1}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(=\dfrac{-3x^2+x+1+x^2-x+1}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(=\dfrac{-2x^2+2}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(=\dfrac{-2\left(x^2-1\right)}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(=\dfrac{-2\left(x-1\right)\left(x+1\right)}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(=\dfrac{-2x+2}{x^2-x+1}\)
\(---\)
c) \(\dfrac{1}{1-x}+\dfrac{1}{1+x}+\dfrac{2}{1+x^2}+\dfrac{4}{1+x^4}\)
\(=\dfrac{1+x}{\left(1-x\right)\left(1+x\right)}+\dfrac{1-x}{\left(1-x\right)\left(1+x\right)}+\dfrac{2}{1+x^2}+\dfrac{4}{1+x^4}\)
\(=\dfrac{1+x+1-x}{1^2-x^2}+\dfrac{2}{1+x^2}+\dfrac{4}{1+x^4}\)
\(=\dfrac{2}{1-x^2}+\dfrac{2}{1+x^2}+\dfrac{4}{1+x^4}\)
\(=\dfrac{2\left(1+x^2\right)}{\left(1-x^2\right)\left(1+x^2\right)}+\dfrac{2\left(1-x^2\right)}{\left(1-x^2\right)\left(1+x^2\right)}+\dfrac{4}{1+x^4}\)
\(=\dfrac{2+2x^2+2-2x^2}{1-x^4}+\dfrac{4}{1+x^4}\)
\(=\dfrac{4}{1-x^4}+\dfrac{4}{1+x^4}\)
\(=\dfrac{4\left(1+x^4\right)}{\left(1-x^4\right)\left(1+x^4\right)}+\dfrac{4\left(1-x^4\right)}{\left(1-x^4\right)\left(1+x^4\right)}\)
\(=\dfrac{4+4x^4+4-4x^4}{1-x^8}\)
\(=\dfrac{8}{1-x^8}\)
#\(Toru\)
\(\dfrac{1}{x+2}+\dfrac{5}{2x^2+3x-2}\\ =\dfrac{1}{x+2}+\dfrac{5}{\left(2x-1\right)\left(x+2\right)}\\ =\dfrac{2x-1}{\left(2x-1\right)\left(x+2\right)}+\dfrac{5}{\left(2x-1\right)\left(x+2\right)}\\ =\dfrac{2x-1+5}{\left(2x-1\right)\left(x+2\right)}\\ =\dfrac{2x+4}{\left(2x-1\right)\left(x+2\right)}\\ =\dfrac{2\left(x+2\right)}{\left(2x-1\right)\left(x+2\right)}\\ =\dfrac{2}{2x-1}\)
__
`x^3+1` chứ cậu nhỉ?
\(\dfrac{-3x^2}{x^3+1}+\dfrac{1}{x^2-x+1}+\dfrac{1}{x+1}\\ =\dfrac{-3x^2}{\left(x+1\right)\left(x^2-x+1\right)}+\dfrac{1}{x^2-x+1}+\dfrac{1}{x+1}\\ =\dfrac{-3x^2}{\left(x+1\right)\left(x^2-x+1\right)}+\dfrac{x+1}{\left(x+1\right)\left(x^2-x+1\right)}+\dfrac{x^2-x+1}{\left(x-1\right)\left(x^2-x+1\right)}\\ =\dfrac{-3x^2+x+1+x^2-x+1}{\left(x+1\right)\left(x^2-x+1\right)}\\ =\dfrac{-2x^2+2}{\left(x+1\right)\left(x^2-x+1\right)}\\ =\dfrac{-2\left(x^2-1\right)}{\left(x+1\right)\left(x^2-x+1\right)}\)
\(=\dfrac{-2\left(x-1\right)\left(x+1\right)}{\left(x+1\right)\left(x^2-x+1\right)}\\ =\dfrac{-2\left(x-1\right)}{x^2-x+1}\)
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Cho A = (3x + 7)(2x + 3) – (3x – 5)(2x + 11); B = x(2x + 1) – x 2 (x + 2) + x 3 – x + 3. Chọn khẳng định đúng
A. A = B
B. A = 25B
C. A = 25B + 1
D. A = B 2
A = (3x + 7)(2x + 3) – (3x – 5)(2x + 11)
= 3x.2x + 3x.3 + 7.2x + 7.3 – (3x.2x + 3x.11 – 5.2x – 5.11)
= 6 x 2 + 9 x + 14 x + 21 – ( 6 x 2 + 33 x – 10 x – 55 ) = 6 x 2 + 23 x + 21 – 6 x 2 – 33 x + 10 x + 55 = 76
B = x ( 2 x + 1 ) – x 2 ( x + 2 ) + x 3 – x + 3 = x . 2 x + x – ( x 2 . x + 2 x 2 ) + x 3 – x + 3 = 2 x 2 + x – x 3 – 2 x 2 + x 3 – x + 3 = 3
Từ đó ta có A = 76; B = 3 mà 76 = 25.3 + 1 nên A = 25B + 1
Đáp án cần chọn là: C
1) 3x+7/11=5x-7/9
2)x-7/4=9/-7+x
3)x-1/-2=8/1-x
cảm ơn nhiều nghen
1) Ta có: \(\dfrac{3x+7}{11}=\dfrac{5x-7}{9}\)
\(\Leftrightarrow9\left(3x+7\right)=11\left(5x-7\right)\)
\(\Leftrightarrow27x+63=55x-77\)
\(\Leftrightarrow27x-55x=-77-63\)
\(\Leftrightarrow-28x=-140\)
hay x=5
Vậy: S={5}
1, 3x+7/11= 5x-7/9
3x-5x=-7/11-7/9
-2x=-140/99
x= 70/99
vậy ...
2, x-7/4=9/-7+x
x-x=7/4-9/7
x không có gt thỏa mãn
3, x-1/-2=8/1-x
x+x =-1/2+8/1
2x =15/2
x =15/4
vậy ...