Question

expand the following (1+ abcd)​

Answer 1

Answer:

1+a.b.c.d is the expanded form.......

Answer 2

Step-by-step explanation:

x+y+z)3 and realize that each term of the expansion must be of degree three and that because x+y+z is cyclic all possible such terms must appear. Those types of terms can be represented by x3,x2y and xyz. If x3 appears, so must y3 and z3. If x2y appears, then so must x2z,y2x,y2z,z2x and z2y. To top it off, xyz is the final term to be included. Therefore

(x+y+z)3=x3+y3+z3+m(x2y+x2z+y2x+y2z+z2x+z2y)+nxyz.

We need only deduce the values of m and n. To build an xyz term, there are 3 ways to select the x and then 2 ways for the y so n=6.

Replacing x,y and z with 1, the left side becomes 27 and the right side becomes 9+6m. Therefore m=3. Now we have it

(x+y+z)3=x3+y3+z3+3(x2y+x2z+y2x+y2z+z2x+z2y)+6xyz.

Remember this! Now make the replacements x=a,y=b and z=−c.