Which of these expressions cannot be simplified by combining like terms?

6fg3+4−4f2g2+f3g−12

6fg3+2f(2fg)+4f2g−10

6fg3+5f2g2+f3g−7

6f3g3+7f2g2+4f3g3−10fg

(f - g)(x) = 5x^3 - 3

step-by-step explanation:

rearrange these functions vertically, with like terms in separate columns:

f(x) = 5x^3 - 2

g(x) =         +1

now subtract, column by column:

(f - g)(x) = 5x^3 - 3

take the logarithm of both sides (the base of the log doesn't matter):

apply the exponent property - this says that :

distribute the log terms on both sides:

group like terms together:

divide through both sides by the coefficient on :

you can do some additional rewriting here using the properties of the logarithm to simplify things if you like: