Solution:
Note that:
[tex]-12.8x+b = -3.2(4x-2.1)+2.4[/tex]
Simplifying the distributive property.
[tex]-12.8x+b = -3.2(4x-2.1)+2.4[/tex]
[tex]-12.8x+b = -12.8x + 6.72+2.4\\[/tex]
Simplifying the RHS.
[tex]-12.8x+b = -12.8x + 9.12[/tex]
Canceling out -12.8x.
[tex]b = 9.12[/tex]
