Vectors! scalars! HELP!!?

write c in the form ra+sb, where r and s are scalars.





a=3i+2j


b+8i+5j


c+7i+9j

Vectors! scalars! HELP!!?
Assume question SHOULD read as:-


a = 3i + 2j


b = 8i + 5j


c = 7i + 9j





ra = 3r i + 2r j


sb = 8s i + 5s j





ra + sb = (3r + 8s) i + (2r + 5s) j


c = 7 i + 9 j


If c = ra + sb:-


3r + 8s = 7


2r + 5s = 9





-6r - 16s = - 14


6r + 15s = 27------ADD


-s = 13


s = - 13





2r = 74


r = 37





c = 37a - 13b
Reply:Thank you for your vote. Report It

Reply:7i+9j=r(3i+2j)+s(8i+5j)


so 3r+8s=7 and 2r+5s=9





now it's easy...


you solve the system


you find


r=37 and s= -13