Question

Solve 12+21y=480
12x+8y=-16
Using elimination method

Answer 1

Answer:

The solution to the given equation is:

$x=\frac{-348}{13} \text { and } y=\frac{496}{13}$

Step-by-step explanation:

Given:$12x+21y=480 ; 12x+8y=-16$

We have to solve the above equation elimination method.

• As we know, the elimination method is the process of eliminating one of the variables in the system of linear equations using addition or subtraction methods in conjunction with multiplication or division of coefficients of the variables.

We are solving in the following way:

We have,

$12x+21y=480 ; 12x+8y=-16$

Let assume,

$12x+21y=480\ \ ...1) \\ 12x+8y=-16\ \ ...2)$

Subtracting eq.2) from eq.1)

$=>12x-12x+21y-8y=480-(-16)\\=>13y=496\\\\=>y=\frac{496}{13}$

Now that we've found y let's plug it back in to solve for x.

Write down an original equation:

$\text { Substituting } \frac{496}{13} \text { for } y \text { in } 12 x+21 y=480 \text { : }$

$12 x+21\left(\frac{496}{13}\right)=480$

$12 x+\frac{10416}{13}=480$

$12 x+\frac{10416}{13}+\frac{-10416}{13}=480+\frac{-10416}{13}(\text { Adding }(-10416) / 13 \text { to both sides })$

$\begin{array}{l}12 x=\frac{-4176}{13} \\\\\frac{12 x}{12}=\frac{\frac{-4176}{13}}{12} \\\\x=\frac{-348}{13}\end{array}$

Hence, we get,

$x=\frac{-348}{13} \text { and } y=\frac{496}{13}$

NOTE:

Q. Solve: 12x+21y=480 ; 12x+8y=-16

Using elimination method