6. Let C be a curve which is the intersection of two surfaces x2+y2=8 and x +z = 3. Find the tangent line to the curve C at the point P(2,2,1) . (10 points)

7.what is the key enzyme for the biosynthesis of deoxyribonucleotides? catalytic activity of the enzyme is turned on and off in response to need for dNTPs? general, this reaction involved oxidation-reduction cycle through two re gulatory enzymes which deliver reducing equivalents. Please write names of these two enzymes? (10 %)