Which equation shows the substitution method being used to solve the system of linear equations? x + y = 6 x = y + 5 A.(y + 5) + y = 6 B.x = (x – 6) + 5 C.x + y = y + 5 D.x + (y + 5) = 6 The system of equations is inconsistent. What are the missing values? 5x + ___y=2 ___x+3y=8 please help will fan and medal
if you know what a substitution method is, then you should be able to tell me. (Hint: you are substituting "y+5" instead of x, based on our second equation)
(and substituting this, into the 1st equation)
i dont really get substitution method
okay, we can go through an example. lets say you have a system below: \(\large\color{black}{ a+b=7 }\) \(\large\color{black}{ a=b+5 }\) what you do is you substitute, \(\large\color{black}{ b+5 }\) instead of a, like this. \(\large\color{black}{ \color{red}{a}+b=7 }\) \(\large\color{black}{ \color{red}{b+2}+b=7 }\)
and then we are able to solve for b, right?
yea
so, in your case though, you have a different system (which is not exactly same, but very similar). \(\large\color{black}{x + y = 6 }\) \(\large\color{black}{ x = y + 5 }\) based on my example, can you tell me how you susbstitute?
so you substitute y+5 instead of x?
yes
and which of the options will this substitution give us?
A?
yes, there you go!
yay! lol and could you help me with the second one?
surely...
The system of equations is inconsistent. What are the missing values? 5x + ___y=2 ___x+3y=8
i didnt really get this one
I am thinking that you just have to find the value of x and the value of y, which would make the 2 equations into parallel lines (but should not be the same exact line).
connection again...
typically, something like this, (where a, b, c, and d, are just numbers.) \(\LARGE\color{black}{ \color{red}{a}~x+\color{blue}{b}~y=\color{darkgoldenrod}{c} }\) \(\LARGE\color{black}{\color{red}{a}~x+\color{blue}{b}~y=\color{green}{d} }\) (and in both equations a and b are same number, but c does not equal d)
in your case you have: \(\LARGE\color{black}{ \color{red}{5}~x+\color{blue}{?_{_2}}~y=\color{darkgoldenrod}{2} }\) \(\LARGE\color{black}{\color{red}{?_{_1}}~x+\color{blue}{3}~y=\color{green}{8} }\)
(by \(\LARGE\color{black}{ \color{blue}{?_{_2}} }\) I mean the second question, and by \(\LARGE\color{black}{\color{red}{?_{_1}} }\) I mean th first question)
im still confused
you need to set your system in a format of \(\LARGE\color{black}{ \color{red}{a}~x+\color{blue}{b}~y=\color{darkgoldenrod}{c} }\) \(\LARGE\color{black}{\color{red}{a}~x+\color{blue}{b}~y=\color{green}{d} }\)
you know from the first equation, that a=5, and c=2, and from the second equation that b=3 and d=8
still confused, or need time to process?
yea im like lost
okay, do you see that in your case, the blank next to x in the second equation, and 5 next to x in a 1st equation should be the same number?
yes
so it shoud be 5x+3y and in the second one it would be the same thing?
yes
So you have: \(\LARGE\color{black}{ \color{red}{5}~x+\color{blue}{3}~y=\color{darkgoldenrod}{2} }\) \(\LARGE\color{black}{\color{red}{5}~x+\color{blue}{3}~y=\color{green}{8} }\)
thanks for your help..again lol
if you subtract the 2 equations the left side is going to be zero, and the right is -6, and you know that 0 doesn't equal to -6. there is the inconsistency.
yw
Join our real-time social learning platform and learn together with your friends!