book Maths Puzzle Numerical Ability

I need help,here's an example:

Rewrite the equation so that y is a function of x.

-4x + y = 9
-3y + 18x = 12

Please keep it simple I'm only 12. Thanks, Tony

Read Solution (Total 0)

book Other Question

The tens digit of a two digit number is twice the units digit. If the digits are reversed, the new number is 36 less than the original number. Find the number. HELP! Find a vector x with ||x||=2 that has the same direction as the vector defined by the points A(3,2,1) and B(1,-1,0).
The opposite direction?