Question 924884
(5x^4 +4x^3 -1) - (7x^2 -6x +6) = 5x^4 +4x^3 -1 -7x^2 +6x -6) 
(5x^4 +4x^3 -1) - (7x^2 -6x +6) = 5x^4 +4x^3 - 7x^2 + 6x - 7