How to calculate with two unknowns

[headbang]

How to calculate with two unknowns.
Solve..

\(\displaystyle 4x-5y=7\)
\(\displaystyle 3y-2x=1\)

 

[evinda]

How to calculate with two unknowns.
Solve..

\(\displaystyle 4x-5y=7\)
\(\displaystyle 3y-2x=1\)

$$ 4x-5y=7 \ \ (*)$$

We multiply both sides of the second equality by $2$, so we have:

$$2 \cdot (3y-2x)=2 \Rightarrow 6y-4x=2 \ \ (**)$$

$$(*)+(**) \Rightarrow 4x-5y+6y-4x=7+2 \Rightarrow y=9$$

$$4x-5y=7 \overset{y=9}{\Rightarrow } 4x-5 \cdot 9=7 \Rightarrow 4x-45=7 \Rightarrow 4x=52 \Rightarrow x=\frac{52}{4} \Rightarrow x=13$$

 

[john1231]

Solving……
Multiply second equation with 2 then
-4x + 6y =2………………….(2)
Now add (1) ,(2)
U will get y value and then substitute y value in (1) or (2)
U will get x value
This is the method for solve any 2 equations…………..keep practcing

 

[topsquark]

U will get y value and then substitute y value in (1) or (2)
U will get x value

Just a comment. As "U" has a specific meaning to it ("U" is defined to be the "union" operator) I recommend that you please type out the whole word "you."

-Dan

 

[john1231]

Thanks for your suggestion.I will rectify my mistake.