Question

integral zero of (x-3)(x-7)

Answer 1

$(x - 3)(x - 7) = 0 \\ x - 3 = 0 \\ x = 3 \\ and \: \\ x - 7 = 0\\ x = 7$

Answer 2

x2-7x-3x+21
x2-10x+21
applying integration
x3/3-10(x2/2)+21x