Question #15aab

1 Answer
Nov 21, 2016

Answer:

#p=3" and " q=4#

Explanation:

The question to be solved is.

#5p-7q=-13to(1)#
#2p+7q=34to(2)#

The aim here is to eliminate one of the variables from the equations by performing operations on them. We then have a one variable equation which we can solve. Then substitute this value into either one of the 2 given equations and solve for the other variable.

I have labelled the equations to assist.

Note that in (1) there is a - 7q and in (2) there is + 7q

Adding these together will eliminate the variable q, which is what we want.

Add (1) and (2) together term by term on both sides.

#rArr7p+0=21rArr7p=21rArrp=3#

Now substitute p = 3 into (1) or (2). I'll choose (2) you can perhaps try (1).

#rArr(2xx3)+7q=34#

#rArr6+7q=34rArr7q=28rArrq=4#

Hope this helps.