The calculation process is as follows:
1 and abcd*9=bcda are still 4 digits, so ABCD = dcba/9.
2. The last digit of 2.dcba is 1, so d=9, and nothing else is possible.
3、 1bc 9 & lt； 1111,so b < 1, so b=0.
4、 10c9*9=
9000
+90 degrees Celsius
+ 8 1
=9c0 1
When the decimal number is 0, the unit of 9*c is 2, which is only satisfied when c=8.
So the answer is 1089.
Common situations and solutions of quartic linear equation with extended data;
A1a2a3a4b1b2b3b4c1c2c3c4d1d3d4e1e2e3e4 are all constants, except for the unknowns w and z.
The values of w and z have been solved, and the values ⒂, ⒃ and ⒄ of y can be obtained by substituting one of the formulas.
Find the value of w Z y, and finally substitute it into any original formula 1234 to find the value of x.
The four unknowns of X y z W have been solved. In the calculation process, the final solution obtained by elimination method has the same value.
Solve equations.
{x+y=4
y+5x= 12
{z+w=9
2z+5w=30
Solution: It can be done according to two binary linear equations.
(5- 1)x= 12-4
4x=8 x=2
y=4-2=2
z+5w= 15
5w=6
w= 1.2 9- 1.2=7.8=z