Question 454259: use substitution method to determine whether the system of linear equations has no solution, one solution,or many solutions
2x - y = 8
x + 4y = 13
Found 5 solutions by mananth, ikleyn, MathTherapy, josgarithmetic, n3:
Answer by mananth(16949)   (Show Source):
You can put this solution on YOUR website! 2 x -1 y = 8 .............1
4 y = 13 -1 x ---------2
/ 4 =
y = 3.25 -0.25 x
Plug the value of y in (1)
2x-1(3.25-0.25x) =8
2x-3.25+ 0.25x=8
2x+0.25 x=8+3.25
2.25x=11.25
/2.25
x=5
Plug the value of x in (1)
2x-y=8
2*5-y=8
10-y=8
-y=-2
y=2
(5,2) is the solution
Answer by ikleyn(53538)  (Show Source):
You can put this solution on YOUR website! .
use substitution method to determine whether the system of linear equations has no solution, one solution,
or many solutions
2x - y = 8
x + 4y = 13
~~~~~~~~~~~~~~~~~~~~~~~~~
The way how @mananth solves this system of equations in his post makes very bad impression.
Normal people would solve it differently, and no one normal teacher in healthy mind would teach
this way as @mananth does.
In this case, you are lucky, because you easy can express 'y' from the first equation
y = 2x - 8
and substitute it into the second equation
x + 4(2x-8) = 13.
Now simplify this equation and find x
x + 8x - 32 = 13,
x + 8x = 13 + 32
9x = 45
x = 45/9 = 5.
Now find 'y' by substituting x= 5 into y = 2x-8 = 2*5-8 = 10-8 = 2.
ANSWER. x = 5, y = 2.
Solved correctly, in a normal way.
Ignore the post by @mananth for the safety of your mind, since it is wrong and inappropriate teaching.
Answer by MathTherapy(10680)  (Show Source):
You can put this solution on YOUR website!
use substitution method to determine whether the system of linear equations has no solution, one solution,or many solutions
2x - y = 8 ----- eq (i)
x + 4y = 13 ----- eq (ii)
Again, this is a real LAUGH! Equation 1 can be easily solved for y, since the coefficient on y is - 1. Likewise,
eq (ii) can be easily solved for x, as too has a coefficient of 1 on x.
So, why on earth would someone choose to SOLVE for a variable that has created FRACTIONS - which most people hate,
and which we normally GET RID OF when solving an equation - when 2 perfectly-stated equations (i) & (ii), already have variables
with coefficients - 1 and 1? This ABSOLUTELY makes NO SENSE, at all!!!
I know another person on this site, who has done the EXACT thing in some, maybe ALL, of her responses!! I wonder who taught them
these RIDICULOUS and NONSENSICAL solving techniques.
This may be one of the reasons why some people FEAR mathematics! I would, if I ever asked for help, and received this response!!
Answer by josgarithmetic(39713)  (Show Source):
Answer by n3(7) (Show Source):
You can put this solution on YOUR website! .
use substitution method to determine whether the system of linear equations has no solution, one solution,or many solutions
2x - y = 8
x + 4y = 13
~~~~~~~~~~~~~~~~~~~~~
For some reason, @josgarithmetic showed up here and once again brought his wrong solution, stating that y = 9.
He shows up at the forum almost every time as I post my correct solution - and every time he tries to corrupt it.
I don't know how he's tolerated on this forum.
For other visitors - my advice is to ignore his posts, for the peace in your mind.
About him, everybody should know three truths:
(a) @josgarithmetic does not know Math,
(b) can not solve Math problems correctly,
(c) can not teach Math.
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