How do you solve y = 3x - 4 and 2x - y = 1?

2 Answers

Answer:

The solution is #(x,y)=(3,5)#

Explanation:

Hence you have two linear equations we have that

#y=3x-4# and #y=2x-1#

since the first parts are equal so the second are

#3x-4=2x-1=>x=3# and #y=2*3-1=5#

Sep 25, 2015

Answer:

#x = 3#
#y = 5#

Explanation:

#y= 3x - 4# #rArr# 1st equation
#2x - y = 1# #rArr# 2nd equation

Since #y# is already the subject of the first equation, all you need to do is substitute #y = 3x - 4# into the 2nd equation!

So,

#2x - (3x - 4) = 1#

Expand the brackets.

#2x - 3x + 4 = 1#

Which gets you:

#-x + 4 = 1#

Move the 4 over so #x# becomes your subject.

#-x = -4 + 1#
#-x = -3#

Switch them over so your #x# is positive!

#3 = x#

To find #y#, just substitute #x = 3# into either the 1st of 2nd equation.

So,

#y = 3(3) - 4#
#y= 9 - 4#
#y = 5#

To check:
Substitute the values of #x# and #y# back into the equation. You will get the same answer.