8x3−8x2+2x
7/2x3/4+17/8x2/3+3/4x1/2+7/8x3/3
\(\dfrac{7}{2}\times\dfrac{3}{4}+\dfrac{17}{8}\times\dfrac{2}{3}+\dfrac{3}{4}\times\dfrac{1}{2}+\dfrac{7}{8}\times\dfrac{3}{3}\)
\(=\dfrac{7\times3}{2\times4}+\dfrac{17\times2}{8\times3}+\dfrac{3\times1}{4\times2}+\dfrac{7}{8}\times1\)
\(=\dfrac{21}{8}+\dfrac{17}{12}+\dfrac{3}{8}+\dfrac{7}{8}\)
\(=\left(\dfrac{21}{8}+\dfrac{3}{8}+\dfrac{7}{8}\right)+\dfrac{17}{12}\)
\(=\dfrac{31}{8}+\dfrac{17}{12}\)
\(=\dfrac{31\times3}{8\times3}+\dfrac{17\times2}{12\times2}\)
\(=\dfrac{93}{24}+\dfrac{34}{24}\)
\(=\dfrac{127}{24}\)
Gỉai các phương trình sau;
a, 3x2 - 8x2 - 2x + 3 = 0
b, x3 - 4x2 + 7x - 6 = 0
c, 2x3 + 7x2 + 7x + 2 = 0
d, 2x3 - 9x + 2 = 0
e, 8x3 - 4x2 + 10x - 5 = 0
a, 3x2 - 8x2 - 2x+3=0
2x(3-8) - 2x+3=0
2x5 - 2x+3=0
2x5 - 2x=0-3=
2x5 - 2x=-3
2x(5-x)=-3
5-x=-3/2
5-x=1,5
x=5-1,5
x=3,5
3,5 nha bn
chúc bn học tốt
happy new year
Bài 1: \(\dfrac{1}{3}\) + \(\dfrac{2}{4}\) + \(\dfrac{3}{5}\) ...........................3(>,<,=)
A.>
B.<
C.=
Bài 2: \(\dfrac{8x7-8x3}{8x2}\) = ?
A.2
B.3
C.4
D.5
x2 ( 8x3 +8x -5\6 ) = 8x ... + 3 + 8x2 +..... - 5\6 x ...
= 8x .... +8x .... - 5/6 x .....
giúp mình với
8x1=
8x2=
8x3=
8x4=
8x5=
8x6=
8x7=
8x8=
8x9=
8x10=
8x1=8
8x2=16
8x3=24
8x4=32
8x5=40
8x6=48
8x7=56
8x8=64
8x9=72
8x10=80
8x1=8
8x2=16
8x3=24
8x4=32
8x5=40
8x6=48
8x7=56
8x8=64
8x9=72
8x10=80
minh nhanh nhat k nha
Bài 5: Tính giá trị các biểu thức sau
a) P(x)=x14- 10x13 + 10x12 -10x11+...+ 10x2 -10x +10 tại x=9
b) Q(x)= x15 - 8x14 + 8x3 - 8x12 +... - 8x2 +8x -5 tại x =7
a)
\(P=\left(x^{14}-9x^{13}\right)-\left(x^{13}-9x^{12}\right)+\left(x^{12}-9x^{11}\right)-...+\left(x^2-9x\right)-\left(x-9\right)+1\)
\(=x^{13}\left(x-9\right)-x^{12}\left(x-9\right)+x^{11}\left(x-9\right)+...+x\left(x-9\right)-\left(x-9\right)+1\)
\(P\left(9\right)=1\)
b)
\(Q=\left(x^{15}-7x^{14}\right)-\left(x^{14}-7x^{13}\right)+\left(x^{13}-7x^{12}\right)-...-\left(x^2-7x\right)+\left(x-7\right)+2\)
\(=x^{14}\left(x-7\right)-x^{13}\left(x-7\right)+x^{12}\left(x-7\right)-...-x\left(x-7\right)+\left(x-7\right)+2\)
\(Q\left(7\right)=2\)
8x1=
8x2=
8x3=
8x4=
8x5=
8x6=
8x7=
8x8=
8x9=
8x10=
8x1=8
8x2=16
8x3=24
8x4=32
8x5=40
8x6=48
8x7=56
8x8=64
8x9=72
8x10=80
8 x 1 = 8
8 x 2 = 16
8 x 3 = 24
8 x 4 = 32
8 x 5 = 40
8 x 6 = 48
8 x 7 = 56
8 x 8 = 64
8 x 9 = 72
8 x 10 = 80
8x1=8
8x2=16
8x3=24
8x4=32
8x5=40
8x6=48
8x7= 56
8x8=64
8x9= 72
8x10=80
Gỉai các phương trình sau;
a, 3x2 - 8x2 - 2x + 3 = 0
b, (x2 - 1)2 = 4x +1
c, 2x3 + 7x2 + 7x + 2 = 0
d, 2x3 - 9x + 2 = 0
e, 8x3 - 4x2 + 10x - 5 = 0
g. x3 + x2 - x√22 - 2√22= 0
h. (x +1 )2 = 9(x - 1)2
Số nghiệm của phương trình 2 x 2 + 2 x - 9 = ( x 2 - x - 3 ) . 8 x 2 + 3 x - 6 + ( x 2 + 3 x - 6 ) . 8 x 2 - x - 3 là:
A. 1
B. 3
C. 2
D. 4