Connect with a community that values knowledge and expertise on IDNLearn.com. Our platform offers reliable and comprehensive answers to help you make informed decisions quickly and easily.

how to use the elimination method for the following equations 16x + 12y = 336 11x + 15y = 312

Sagot :

Given the system of equations:

[tex]\begin{gathered} 16x+12y=336\text{ \lparen1\rparen} \\ 11x+15y=312\text{ \lparen2\rparen} \end{gathered}[/tex]

The elimination method consists of multiplying either of the two equations in order to have the coefficients of x or y with the same value and be able to add or subtract.

In this case we are going to multiply the equation (2) by 16/11:

[tex]\begin{gathered} \frac{16}{11}(11x+15y)=\frac{16}{11}*(312) \\ 16x+\frac{16*15}{11}y=\frac{16*312}{11} \\ \\ 16x+\frac{240}{11}y=\frac{4992}{11}\text{ \lparen3\rparen} \end{gathered}[/tex]

Now, subtracting (1) - (3)

[tex]\begin{gathered} 16x+12y=336 \\ - \\ 16x+\frac{240}{11}y=\frac{4992}{11} \end{gathered}[/tex]

This is going to be eual to:

[tex](16x-16x)+(12y-\frac{240}{11}y)=(336-\frac{4992}{11})[/tex]

Where: 16x-16x=0, therefore:

[tex]12y-\frac{240}{11}y=336-\frac{4992}{11}[/tex]

Solving for y:

[tex]\begin{gathered} -\frac{108}{11}y=-\frac{1296}{11} \\ 108y=1296 \\ y=\frac{1296}{108}=12 \end{gathered}[/tex]

Finally, replacing the value of y in (1) to find x:

[tex]\begin{gathered} 16x+12(12)=336 \\ 16x=336-144 \\ 16x=192 \\ x=\frac{192}{16}=12 \end{gathered}[/tex]

Answer: the solution of the system is x=12, y=12.