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sommersquid
What is the value of the x variable in the solution to the following system of equations? 7x - 2y = 21 4x + y = 57
ummm is this algebra 2?
algebra 1, 2nd year taking it again
once i find the y , i put it in the the first equation right?
I think so... i asked somebody if they could come and help since I need to understand this better as well since i sort of forgot haha :)
sorry hold on lemme see if that person will come... ;/
Hi @jim_thompson5910 thanks for coming :) I also do not understand this 100% haha :) u got my message then i take it? :)
double everything in the second equation to get 8x + 2y = 114
and hi @apoorvk thanks for coming also!!! i appreciate it :)
ohkay, @iheartfood - go on and post what you would have done in this problem, and don't worry if it's right or wrong.. :)
Now add the two equations 7x - 2y = 21 8x + 2y = 114 -------------- 15x + 0y = 135 Now solve 15x = 135 for x
well i know you're supposed to solve for one, but i did not know you could do that (what @jim_thompson5910 wrote.... so that is another way you can do it??
is that how you do it?? simplify it into one larger equation??
that's one way to do it, there is more than one way
okay, what's another way to do it?? i think i remember that you can solve one equation and then plug it in but i couldn't do it for this one... ;/
you isolate one variable in terms of the other then you substitute 4x + y = 57 y = 57 - 4x ------------------ 7x - 2y = 21 7x - 2(57-4x) = 21 Now solve for x
x = 9 for my problem right? (:
oh okay cool :) soooo x=45??
you are correct, the answer to the first piece is x = 9
hmm how did you get x = 45?
now that you know that x = 9, use this to find y
sorry by bad... lol it's 9 sorry!!
sooo you plug it in right??
so y=21 ???? and x=9 ???
yes, pick any equation dealing with y and plug in x = 9 7x - 2y = 21 7(9) - 2y = 21 Solve for y
and yes, y = 21
oh i used the second equation.. haha but it works both ways :) u get the same answer for both right?
oh the question was just "What is the value of the x variable in the solution to the following system of equations?" so they just want x Usually, they'll want both x and y
yes either equation works
oh okay cool! thanks!! i totally understand it now... :) what a refresher!! And @sommersquid did that help??? And thanks again for coming @jim_thompson5910 :)
yesss, it really did (: i just needed help with the second step but i got it now (: thank you so much everyone