Use factor method to evaluate:

39x³(50x² - 98) ÷ 26x²(5x + 7)

$\dfrac{39x^3 (50x^2 - 98)}{26x^2(5x + 7)}\\[1em] = \dfrac{3x (50x^2 - 98)}{2(5x + 7)}\\[1em] = \dfrac{3x \times 2(25x^2 - 49)}{2(5x + 7)}\\[1em] = \dfrac{6x((5x)^2 - (7)^2)}{2(5x + 7)}\\[1em] = \dfrac{3x(5x - 7)(5x + 7)}{(5x + 7)}\\[1em] = \dfrac{3x(5x - 7)\cancel{(5x + 7)}}{\cancel{(5x + 7)}}\\[1em] = 3x(5x - 7)$

Hence, 39x³(50x² - 98) ÷ 26x²(5x + 7) = 3x(5x - 7)