Mohon dibantu. Terimakasih

lim (x^2-4)/(2-√(x+2) untuk x ->2
lim (x^2-4)(2+√(x+2)/(2-√(x+2))(2+√(x+2))
lim (x-2)(x+2)(2+√(x+2)/(4-(x+2))
lim (x-2)(x+2)(2+√(x+2)/(2-x)
lim (x+2)(x-2)(2+√(x+2)/-(x-2)
= - lim (x+2)(2+√(x+2) untuk x --> 2
= - (2+2)(2+√(2+2)
= - (4)(4)
= -16
jadi a = -16
4-a = 4 - -16 = 4+16= 20