Gather like terms. Like terms are terms with the same variable and degree(exponent).
[tex] {3.3m}^{2} + {4.9m}^{2} + 6.6c - 3.6c - 2.3c[/tex]
I just rearranged the formula so that the like terms with with each other. If you do this though be very careful about the signs and don't mix them up!
Simplifying this further, you just add or subtract which ever coefficients of the like terms. This gives you,
[tex] {8.2m}^{2} + 0.7c[/tex]
Hope this helps!
