1. l:r = 2i – 3j + 5k + t ( i – j – k ), point P(0,-1,7) lies on the line l. The angle between OP and the line l.

2. Point A(1,4,-3), B(5,6,-1) and C(-3,1,2). The plane π contains points A, B and C. Find the angle between the line OC and π.

Please help me to find a correct and show me the way to do it

I just got it wrong so please help.