Let
b----------> the missing term
we have
[tex](10x - 4x^{2} )- (7x + b) = 3x - 6x^{2}[/tex]
Combine like terms in the left side
[tex](10x-7x)+(-b - 4x^{2}) = 3x - 6x^{2}[/tex]
[tex](3x)+(-b - 4x^{2}) = 3x - 6x^{2}[/tex]
Simplify
[tex](-b - 4x^{2}) = - 6x^{2}[/tex]
[tex]b = 6x^{2}-4x^{2}[/tex]
[tex]b = 2x^{2}[/tex]
therefore
the answer is
the missing term is equal to [tex]2x^{2}[/tex]
