Find C1 and C2.(MATH)

[0.6:0.4]=C1*[3;5]+C2[1;-1]
Matrices are in columns.
How to find C1 and C2? Please show steps.THANK YOU!

[0.6:0.4]=C1*[3;5]+C2[1;-1]

0.6 = 3C1 + C2
0.4 = 5C1 - C2

You need to solve the two equations simultaneously. you can use elimination.
Add the two equations:

0.6 = 3C1 + C2
0.4 = 5C1 - C2
-----------------------
1= 8C1

==> C1 = 1/8 = 0.125

0.4 = 5C1 -C2 ==> 0.4 = 0.625 - C2

C2 = 0.625 -0.4 = 0.225