SOLUTION: Using Substitution 4x + 2y = 1 2x + 3y = .70 Solving for X in the first problem 4x + 2y - 2y = 1 - 2y 4x = 1-2y 4x/4 = (1-2y)/4 x = (1 - 2y)/4 Substitute x into first e

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Using Substitution 4x + 2y = 1 2x + 3y = .70 Solving for X in the first problem 4x + 2y - 2y = 1 - 2y 4x = 1-2y 4x/4 = (1-2y)/4 x = (1 - 2y)/4 Substitute x into first e      Log On


   

Question 168889: Using Substitution
4x + 2y = 1
2x + 3y = .70
Solving for X in the first problem
4x + 2y - 2y = 1 - 2y
4x = 1-2y
4x/4 = (1-2y)/4
x = (1 - 2y)/4
Substitute x into first equation (this is where I get lost)
2(1-2y/4) + 3y = .70
the example on this website says it should be 2(1+2y)/4+3y=.70, but if x = (1-2y)/4, how can you just change it to the 1+2y? Then also how do I solve the problem? If you could give me step by step with explanations so I understand that would be very helpful. This is my calculations:
2-4y/4 + 3y = .70 (multiplied 2 by everything in parentheses)
2-y+3y=.70 (4's cancel eachother out)
2+2y=.70 (3y minus 1y = 2y)
2+2y/2 = .70/2 (divide both sides by 2)
1+y = .35
y = .35 - 1 (subtract 1 from each side)
y = -.65
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
You're on the right track.
Watch the parentheses though, they got you in trouble in the next line.
2%28%281-2y%29%2F4%29+%2B+3y+=+.70
%281-2y%29%2F2%2B3y=0.70
%281-2y%29%2B6y=1.40Multiply both sides by 2 to get rid of denominators.
1%2B4y=1.40
4y=0.40
y=0.1
Then from above
x+=%281+-+2y%29%2F4
x=%281-.2%29%2F4
x=0.8%2F4
x=0.2