The 4 litres of red has to be 2 parts of the mixture, so each part will be 2 litres. Therefore 3 parts of cream will be 6 litres and the one part of blue will be 2 litres.
4x - 2y = 14
y = 0.5x -1
Get just one variable on one side for both equations.
4x - 2y = 14 ⇒ 4x = 2y + 14 ⇒ 4x - 14 = 2y
y = 0.5x - 1 ⇒ x - 2 = 2y
Use the transitive property and then solve for x.
x-2 = 4x-14
12 = 3x
x = 4
<em>Edit: Apprently I didn't use substitution. Oops! Sorry...</em>
Tan x =opposite/ adjacent =9/5
x= arctan(9/5)≈61
