If vectors a and b is respectively 3x+y and x-2y, find x and y interms of a and b
3x+y = a
x-2y = b
so, since x = 2y+b,
3(2y+b)+y = a
6y+3b+y=a
7y = a-3b
y = (a-3b)/7
x = 2y+b = 2*(a-3b)/7 + b = (2a-6b+7b)/7 = (2a+b)/7
x-2y = b
so, since x = 2y+b,
3(2y+b)+y = a
6y+3b+y=a
7y = a-3b
y = (a-3b)/7
x = 2y+b = 2*(a-3b)/7 + b = (2a-6b+7b)/7 = (2a+b)/7