Step-by-step explanation:
very simple : the terms with the same base (either a specific number or a variable with the same exponent, or a function ...) can be combined.
4a - 3b + 6a
which terms here have the same base ?
ah, 4a and 6a refer to the same variable (and with the same exponent : 1, as a = a¹).
therefore, I can combine them :
4a + 6a = a×(4+6) = a×10 or simply 10a
so the result is
10a - 3b
