please tolong bantu dijawab kk

1) Lim cos 2x / (cos x - sin x)
= Lim (cos^2 x - sin^2 x) / (cos x - sin x)
= Lim (cos x + sin x)(cos x - sin x)/(cos x - sin x)
= Lim (cos x + sin x)
= cos π/4 + sin π/4
= 1/2 √2 + 1/2 √2
= √2

2) Lim (sin 2x) / (3 - √(2x + 9)) . (3 + √(2x + 9))/(3 + √(2x + 9))
= Lim (sin 2x)(3 + √(2x + 9)) / (9 - (2x + 9))
= Lim (3 + √(2x + 9)) (sin 2x)/(-2x)
= (3 + √(2.0 + 9)) . 2/-2
= (3 + √9) . -1
= -6