SOLUTION: can you please solve this by the substitution method? y - 2x = -7.5 3x - 5y = 3.2 Thank you for your assistance.

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: can you please solve this by the substitution method? y - 2x = -7.5 3x - 5y = 3.2 Thank you for your assistance.      Log On


   

Question 137243This question is from textbook
: can you please solve this by the substitution method?
y - 2x = -7.5
3x - 5y = 3.2
Thank you for your assistance. This question is from textbook

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
can you please solve this by the substitution method?
y - 2x = -7.5
3x - 5y = 3.2
:
Arrange the 1st equation for substitution:
y - 2x = -7.5
y = 2x - 7.5; added 2x to both sides:
:
In the 2nd equation, substitute (2x-7.5) for y, solve for x
3x - 5(2x-7.5) = 3.2
:
3x - 10x + 37.5: multiply what's inside the brackets (neg outside changes signs inside the brackets)
:
3x - 10x = 3.2 - 37.5; subtracted 37.5 from both sides
:
-7x = -34.3
x = %28-34.3%29%2F%28-7%29
x = +4.9
:
Use the equation we derived from the 1st equation to find y:
y = 2x - 7.5
:
Substitute 4.9 for x
y = 2(4.9) - 7.5
;
y = 9.8 - 7.5
:
y = 2.3
:
:
Check solutions by substitution in the 2nd equation:
3x - 5y = 3.2
3(4.9) - 5(2.3) =
14.7 - 11.5 = 3.2, confirms our solution
:
:
Do you think you can do these kind of problems now?