nilai lim x-7 2x^2-8x-42/x^2-10x+21

(2x² - 8x - 42)/(x² - 10x + 21)
= (2(x² - 4x - 21))/(x² - 10x + 21)
= (2(x - 7)(x + 3))/((x - 7)(x - 3))
= (2(x + 3))/(x - 3)
= (2x + 6)/(x - 3)
= (2(7) + 6)/(7 - 3)
= (14 + 6)/4
= 20/4
= 5