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Mathematics 11 Online
OpenStudy (wintersuntime):

Can someone be nice enough to help me please ?

OpenStudy (micheal1234):

need help http://openstudy.com/study#/updates/56205589e4b0cadb1e1179a0

OpenStudy (wintersuntime):

consider this system of equation y=3x and 3x+y=9

OpenStudy (wintersuntime):

Solving systems using substitution

OpenStudy (wintersuntime):

I have to solve them using substitution and equal values method

OpenStudy (micheal1234):

i think x=3

OpenStudy (photon336):

@Wintersuntime. they're telling you that y = 3x right? so you plug this into the second equation 3x+y = 9 see what I did below? y = 3x 3x+y = 9 3x+3x = 9 6x = 9 x = 9/6 Check this. y = 3(9/6) x = 9/6, y = 4.5 3(9/6) + 4.5 = 9 4.5 + 4.5 = 9

OpenStudy (photon336):

so we find that x = 1.5 and y = 4.5 you can plug both these values into the two equations and you'll find that they satisfy them both.

OpenStudy (wintersuntime):

Thats substitution or equal values method ?

OpenStudy (photon336):

that's substitution because we substituted y = 3x into the second equation where we had y.

OpenStudy (wintersuntime):

How would be in a fraction ? is it 9/6

OpenStudy (photon336):

Yeah that's 3/2 or 1.5

OpenStudy (wintersuntime):

How do i plug them back to the equation ?

OpenStudy (photon336):

Let me give you a problem

OpenStudy (wintersuntime):

sorry im really dumb at math

OpenStudy (photon336):

@wintersuntime can you solve this and show me what you get step by step? y = 2x 2x+y = 16

OpenStudy (wintersuntime):

add 2x both sides first

OpenStudy (photon336):

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