1) ∫(4-6x)dx = ∫4dx - ∫6xdx = 4x - 6x²/2 = 4x-3x²
2) ∫(6-2x)dx = ∫6dx - ∫2xdx = 6x - 2x²/2 = 6x-x²
3) ∫(5x³-4)dx = ∫5x³dx - ∫4dx = 5x⁴/4 - 4x
