1 1/2 x 1 1/3 x 1 1/4 x .......x 1/1963 tìm số .....
1 1/2 x 1 1/3 x 1 1/4 x .......x 1/1963
\(1\frac{1}{2}.1\frac{1}{3}.1\frac{1}{4}....1\frac{1}{1963}\)\(=\frac{3}{2}.\frac{4}{3}.\frac{5}{4}.\frac{6}{5}......\frac{1964}{1963}\)\(=\frac{3.4.5.6.....1964}{2.3.4.5.....1963}=\frac{1964}{2}=982\)
1 1/2 x 1 1/3 x 1 1/4 x .......x 1 1/1963
=3/2 x 4/3 x 5/4 x...x1964/1963
=1964/2
=982
1 1 1 1
1 _ X 1_ X 1_ X... X____
2 3 4 1963
1.Tìm X thuộc Z:
a) 3.(X-1).(X-5)= -18
b) 5.(x-2) . (x+3)=15
c) X+(X+1)+(X+2)+...+2008+2009=2009
d) 1963+1962+...+(X+1)+X=3925
1.Tìm X thuộc Z:
a) 3.(X-1).(X-5)= -18
b) 5.(x-2) . (x+3)=15
c) X+(X+1)+(X+2)+...+2008+2009=2009
d) 1963+1962+...+(X+1)+X=3925
a.(x-1)(x-5)=-18
<=>x2-5x-x+5=-18
<=>x2-5x-x+5+18=0
<=>x2-6x+23=0
Denta =(-6)2-4.1.23=-56 PTVN
b.5(x-2)(x+3)=15
<=>5(x2+3x-2x-6)=15
<=> 5x2 +15x-10x-30=15
<=> 5x2+15x-10x-30-15
<=> 5x2 +5x -45=0
Denta = 52-4.5.(-45)=525>0
Phương trình có 2 nghiệm phân biệt
x1= -5+√525/10=....
x2=-5-√525/10=....
1.Tìm X thuộc Z:
a) 3.(X-1).(X-5)= -18
b) 5.(x-2) . (x+3)=15
c) X+(X+1)+(X+2)+...+2008+2009=2009
d) 1963+1962+...+(X+1)+X=3925
1.Tìm X thuộc Z:
a) 3.(X-1).(X-5)= -18
b) 5.(x-2) . (x+3)=15
c) X+(X+1)+(X+2)+...+2008+2009=2009
d) 1963+1962+...+(X+1)+X=3925
a) \(3.\left(x-1\right).\left(x-5\right)=-18\)
\(\left(3x-3\right)\left(x-5\right)=-18\)
\(3x^2-15x-3x+16+18=0\)
\(3x^2-18x+34=0\)
\(3.\left(x^2-6x+\frac{34}{3}\right)=0\)
đén đây tự phân tích tiếp nha
câu sau tương tự
1.Tìm X thuộc Z:
a) 3.(X-1).(X-5)= -18
b) 5.(x-2) . (x+3)=15
c) X+(X+1)+(X+2)+...+2008+2009=2009
d) 1963+1962+...+(X+1)+X=3925
1.Tìm X thuộc Z: (Toán lớp 6)
a) 3.(X-1)-(X-5)= -18
b) 5.(X-2)-(X+3)=15
c) X + (X+1)+(X+2)+...+2008+2009=2009
d) 1963+1962+...+(X+1)+X=3925
1.Tìm X thuộc Z: (Toán lớp 6)
a) 3.(X-1)-(X-5)= -18
b) 5.(X-2)-(X+3)=15
c) X + (X+1)+(X+2)+...+2008+2009=2009
d) 1963+1962+...+(X+1)+X=3925