x + 8 ⋮ x + 3
Tính
8 x 1 = ..... 8 x 2 = ..... 8 x 3 = ..... 8 x 4 = .....
1 x 8 = ..... 2 x 8 = ..... 3 x 8 = ..... 4 x 8 = .....
8 x 5 = ..... 8 x 6 = ..... 8 x 7 = ..... 8 x 8 = .....
5 x 8 = ..... 6 x 8 = ..... 7 x 8 = ..... 8 x 9 = .....
8 x 1 = 8 8 x 2 = 16 8 x 3 = 24 8 x 4 = 32
1 x 8 = 8 2 x 8 = 16 3 x 8 = 24 4 x 8 = 32
8 x 5 = 40 8 x 6 = 48 8 x 7 = 56 8 x 8 = 64
5 x 8 = 40 6 x 8 = 48 7 x 8 = 56 8 x 9 = 72
Bài 1: Tìm x
x-7/12.x=5/24-3/8.x
(x-1/2).(-3-x/2)=0
x-3/-2=-8/x-3
=) (x-3).(x-3)=(-2).(-8)
(x-3) mũ 2 =16
\(a,x-\dfrac{7}{12}x=\dfrac{5}{24}-\dfrac{3}{8}x\)
\(\Leftrightarrow\dfrac{5}{12}x+\dfrac{3}{8}x=\dfrac{5}{24}\)
\(\Leftrightarrow\dfrac{19}{24}x=\dfrac{5}{24}\Leftrightarrow x=\dfrac{5}{19}\)
Vậy x = 5/19
\(b,\left(x-\dfrac{1}{2}\right)\left(-3-\dfrac{x}{2}\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{1}{2}=0\\-3-\dfrac{x}{2}=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=-6\end{matrix}\right.\)
Vậy x = 1/2 hoặc x = -6
\(c,\dfrac{x-3}{-2}=\dfrac{-8}{x-3}\)
\(\Leftrightarrow\left(x-3\right)^2=16\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=4\\x-3=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=7\\x=-1\end{matrix}\right.\)
Vậy x = 7 hoặc x = -1
\(P\left(x\right)=\sqrt[3]{\sqrt{x+8}\left(x^4+8x^3+12x\right)+6x^3+48x^2+8}\)
đặt \(A=\sqrt{x+8}\left(x^4+8x^3+12x\right)+6x^3+48x^2+8\)
\(=\sqrt{x+8}\left(x^4+8x^3\right)+6x^2\left(x+8\right)+12x\sqrt{x+8}+8\)
\(=\sqrt{\left(x+8\right)^3}x^3+3\sqrt{\left(x+8\right)^2}x^22+3\sqrt{\left(x+8\right)}x4+8\)
\(=\left(x\sqrt{x+8}+2\right)^3\)
\(\Rightarrow P\left(x\right)=x\sqrt{x+8}+2\)
\(P\left(x\right)=\sqrt[3]{\sqrt{x+8}.\left[x^3\left(x+8\right)+12x\right]+6x^2\left(x+8\right)+8}\)
Đặt: \(\sqrt{x+8}=a>0\) => \(x+8=a^2\)
Khi đó ta có:
\(P\left(x\right)=\sqrt[3]{a\left(x^3a^2+12x\right)+6x^2a^2+8}\)
\(=\sqrt[3]{x^3a^3+12xa+6x^2a^2+2}\)
\(=\sqrt[3]{\left(ax+2\right)^3}\)
\(=ax+2\)
\(=x\sqrt{x+8}+2\)
8 x 0 =
8 x 8 =
8 x 2 =
8 x 4 =
8 x 6 =
8 x 9 =
8 x 3 =
8 x 7 =
8 x 10 =
8 x 0 =0
8 x 8 =64
8 x 2 =16
8 x 4 =32
8 x 6 =48
8 x 9 =72
8 x 3 =24
8 x 7 =56
8 x 10 =80
8 x 0 =0
8 x 8 =64
8 x 2 =16
8 x 4 =32
8 x 6 =48
8 x 9 =72
8 x 3 =24
8 x 7 =56
8 x 10 =80
8 x 0 =0
8 x 8 =64
8 x 2 =16
8 x 4 =32
8 x 6 =48
8 x 9 =72
8 x 3 =24
8 x 7 =56
8 x 10 =80
Tính
8 x 1 = ..... 8 x 3 = ..... 8 x 5 = ..... 8 x 7 = ..... 8 x 9 = .....
8 x 2 = ..... 8 x 4 = ..... 8 x 6 = ..... 8 x 8 = ..... 8 x 10 = .....
8 x 1 = 8 8 x 3 = 24 8 x 5 = 40 8 x 7 = 56 8 x 9 = 72
8 x 2 = 16 8 x 4 = 32 8 x 6 = 48 8 x 8 = 64 8 x 10 = 80
Tính nhẩm
8 x 1 =
8 x 5 =
8 x 0 =
8 x 8 =
8 x 2 =
8 x 4 =
8 x 6 =
8 x 9 =
8 x 3 =
8 x 7 =
8 x 10 =
8 x 1 = 8
8 x 5 = 40
8 x 0 = 0
8 x 8 = 64
8 x 2 = 16
8 x 4 = 32
8 x 6 = 48
8 x 9 =72
8 x 3 = 24
8 x 7 = 56
8 x 10 = 80
8 x 1 = 8
8 x 5 = 40
8 x 0 = 0
8
64
16
32
48
72
24
56 80
1. Cho hai đa thức: R(x)=-8(x^4)+6(x^3)+2(x^2)+5x-1 và S(x)=(x^4)-8(x^3)+2x+3. Tính: a) R(x)+S(x); b) R(x)-S(x). 2. Xác định bậc của hai đa thức là tổng, hiệu của: A(x)=8(x^5)+6(x^4)+2(x^2)-5x+1 và B(x)=8(x^5)+8(x^3)+2x-3.
Tính nhẩm
8 x 3 =
8 x 2 =
8 x 4 =
8 x 1 =
8 x 5 =
8 x 6 =
8 x 7 =
0 x 8 =
8 x 8 =
8 x 10 =
8 x 9 =
8 x 0 =
Học sinh tự nhẩm và ghi như sau:
8 x 3 = 24
8 x 2 = 16
8 x 4 = 32
8 x 1 = 8
8 x 5 = 40
8 x 6 = 48
8 x 7 = 56
0 x 8 = 0
8 x 8 = 64
8 x 10 = 80
8 x 9 = 72
8 x 0 = 0
1.24
2.16
3.32
4.8
5.40
6.48
7.56
8.0
9.64
10.80
11.72
12.0
\(b) 5^{x+4} - 3 . 5^{x+3} = 2. 5^{11} \)
\(c) 2 . 3^{x+2} + 4 . 3^{x+1} = 10 . 3 ^{6}\)
\(d) 6 . 8 ^ {x-1} + 8 ^ {x+1} = 6 . 8^ {19} + 8 ^ {21}\)
b) Ta có: \(5^{x+4}-3\cdot5^{x+3}=2\cdot5^{11}\)
\(\Leftrightarrow2\cdot5^{x+3}=2\cdot5^{11}\)
\(\Leftrightarrow x+3=11\)
hay x=8
c) Ta có: \(2\cdot3^{x+2}+4\cdot3^{x+1}=10\cdot3^6\)
\(\Leftrightarrow18\cdot3^x+12\cdot3^x=10\cdot3^6\)
\(\Leftrightarrow30\cdot3^x=30\cdot3^5\)
Suy ra: x=5
d) Ta có: \(6\cdot8^{x-1}+8^{x+1}=6\cdot8^{19}+8^{21}\)
\(\Leftrightarrow6\cdot\dfrac{8^x}{8}+8^x\cdot8=6\cdot8^{19}+64\cdot8^{19}\)
\(\Leftrightarrow8^x\cdot\dfrac{35}{4}=70\cdot8^{19}\)
\(\Leftrightarrow8^x=8^{20}\)
Suy ra: x=20
tính theo mẫu :
Mẫu : ( 5 / 8 x 3 / 4 ) x 4 / 5 = 5 / 8 x ( 3 / 4 x 4 / 5 ) = 5 / 8 x 3 / 5 = 3 / 8
a) ( 4 / 9 x 3 / 7 ) x 7 / 4
b) ( 6 / 5 x 4 / 5 ) x 25 / 16
c) ( 7 / 8 x 16 / 9 ) x 3 / 14
a, \(\left(\frac{4}{9}.\frac{3}{7}\right).\frac{7}{4}=\frac{4}{9}\left(\frac{3}{7}.\frac{7}{4}\right)=\frac{4}{9}.\frac{3}{4}=\frac{3}{9}=\frac{1}{3}\)
b, \(\left(\frac{6}{5}.\frac{4}{5}\right).\frac{25}{16}=\frac{6}{5}\left(\frac{4}{5}.\frac{25}{16}\right)=\frac{6}{5}.\frac{5}{4}=\frac{6}{4}=\frac{3}{2}\)
c, \(\left(\frac{7}{8}.\frac{16}{9}\right).\frac{3}{14}=\frac{7}{8}\left(\frac{16}{9}.\frac{3}{14}\right)=\frac{7}{8}.\frac{8}{21}=\frac{7}{21}=\frac{1}{3}\)
a,
b,
c,
Nếu đúng thì k cho mình nhé bạn!