Its 2x^2-4x, to check it add it to 3x^2-2x or
2x^(2)-4x+3x^(2)-2x
The equation is false because the real answer is z5/4. The variable doesn't just disappear.
The average rate of change between two input values is the total change of the function values (output values) divided by the change in the input values.
You carry the 7 add the 6 put a little bit of whip cream and you got a cake ta da