Answer:
3
Step-by-step explanation:
system of equations:
[tex]a+b=4[/tex]
[tex]a^3+b^3=28[/tex]
[tex]a=4-b[/tex]
plug in for a in other equation and solve
[tex](4-b)^3+b^3=28[/tex]
[tex]64-48b+12b^2-b^3+b^3=28[/tex]
[tex]64-48b+12b^2=28[/tex]
[tex]0=36-48b+12b^2[/tex]
[tex]0=3-4b+b^2[/tex]
[tex]0=(b-3)(b-1)[/tex]
[tex]b = 3[/tex]
or
[tex]b=1[/tex]
plug into other equation to get a
[tex]a=4-b=4-3=1[/tex]
or
[tex]a=4-b=4-1=3[/tex]
multiply together
[tex]1*3=3[/tex]
