I believe his brother is 4 at the moment, since 4*3 is 12. in 4 years John will be 16 and his brother will be 8, and 8 is half of 16. so 16?
A plane parallel to vectors <9, 6, 2> and <-8, -4, -5> is given by

Since the plane passes through point (5, -5, 8), then
-22(5) + 29(-5) + 12(8) = -110 - 145 + 96 = -159
The required plane is -22x + 29y + 12z = -159
z = 11/6x - 29/12y - 53/4
Answer is D it moves 8 to the right and up 4
2(30)=60+30=90. thats a right angle which is 90 degrees so the answer is 30