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IN DESPERATE NEED OF HELP :(

4x - 9y =9


-x + 3y = 6



Rewrite one of the two equations above in the form ax + by = c, where a, b, and c are constants, so that the sum of the new equation and the unchanged equation from the original system results in an equation in one variable.

Respuesta :

afrazi01p8qv5j

So, the problem is asking for one of the equations to be rewritten. Lets rewrite the second one. The way to create a system of equations that will cancel is to create a situation where the a or b of both equations add to 0. In this case, we can multiply the second equation by 3 to turn the 3y into 9y.


[tex]3(-x + 3y) = (6)3[/tex]

[tex]-3x + 9y = 18[/tex]


Our new system is [tex]4x - 9y =9[/tex] and [tex]-3x + 9y = 18[/tex]. We can now add these together.


[tex]4x - 9y = 9[/tex]

[tex]-3x + 9y = 18[/tex]


Adding each part straight down, we get the equation:

[tex]x + 0 = 27[/tex]


We now have an equation with a single variable, which also tells us that x is equal to 27.


Extra: To find the value of y after this, we merely need to plug in the value of x to one of the equations and solve for y.


[tex]-27 + 3y = 6[/tex]

[tex]3y = 33[/tex]

[tex]y = 11[/tex]