These vectors u and z are given in the (x,y) form
Given u = (3,-7) and z = (7,8)
Therefore,
2u = ((2 x 3), (2 x 7)) = (6, 14)
5z = ((5 x 7), (5 x 8)) = (35, 40)
Therefore, 2u + 5z, we add the x component and the y component
This gives 2u + 5z = ((6 + 35), (14 + 40)) = (41, 75)
Recall that they are given in the (x,y) form.
Therefore, the x component of the vector w = 41