SOLUTION: 1) If p=2i-3j, q=3i+5j and r=i+j find 2p+q-3r. 2) The position vectors of the points P,Q,R and S relative to the origin O are: P=Si-6j, Q=4i+4j, R=8i-9j, S=10i-25j respectively,

Algebra ->  Vectors -> SOLUTION: 1) If p=2i-3j, q=3i+5j and r=i+j find 2p+q-3r. 2) The position vectors of the points P,Q,R and S relative to the origin O are: P=Si-6j, Q=4i+4j, R=8i-9j, S=10i-25j respectively,      Log On


   

Question 1028187: 1) If p=2i-3j, q=3i+5j and r=i+j find 2p+q-3r.
2) The position vectors of the points P,Q,R and S relative to the origin O are: P=Si-6j, Q=4i+4j, R=8i-9j, S=10i-25j respectively,
I) 5p-3q+4r
Thank you :)
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
1) If p=2i-3j, q=3i+5j and r=i+j find 2p+q-3r.
Since p=2i-3j, q=3i+5j and r=i+j,

replace p by (2i-3j), q by (3i+5j), r by (i+j)

in  2p+q-3r, and get

2(2i-3j)+(3i+5j)-3(i+j)

Now use the distributive principle to remove
the parentheses:

4i-6j+3i+5j-3i-3j

Now collect like terms:

4i-4j

2) The position vectors of the points P,Q,R and S relative
to the origin O are: P=Si-6j, Q=4i+4j, R=8i-9j, S=10i-25j
respectively,
I) 5p-3q+4r
Are you mixing capital letters with small letters and 
using them to stand for the same things?

Do you mean 5P-3Q+4R and not 5p-3q+4r?  What do you mean by 
the S in P=Si-6j?  Is that the same S as in S=10i-25j?

Edwin