Respuesta :
You can use the constant which if multiplied with the coefficient of x in first equation, ends up making it negative and of equal magnitude to the coefficient of x variable in second equation.
The first equation should be multiplied by the constant 5
How to choose what quantity to multiply the first equation?
This method is actually called method of elimination to solve a system of linear equations.
We make one specific variable's coefficients of equal magnitude so that we can subtract or add the equations and eliminate that variable to make it easy to get the value of the other variable which will then help in getting the value of the first variable (if working in dual variable system).
If we have equations:
[tex]a_1x + b_1y = c_1\\a_2 x + b_2y = c_2\\[/tex]
then, if we want to eliminate variable x, then we have to multiply equation 1 with [tex]-\dfrac{a_2}{a_1}[/tex] which will make coefficient of x in first equation as [tex]a_1 \times -\dfrac{a_2}{a_1} = -a_1[/tex]
Then adding both equation will eliminate the variable x.
We could've skipped that -ve sign and at then end, instead of adding, we could've subtracted the equations.
Using above method for getting the needed constant
The system of equation we've got is
[tex]\dfrac{2}{5}x + 6y = -10\\\\-2x -2y = 40[/tex]
Thus, we have the constant needed = [tex]-\dfrac{a_2}{a_1} = -\dfrac{-2}{2/5} = 5[/tex]
The resultant system of equation we will get is:
[tex]2x + 30y = -50\\\\-2x -2y = 40[/tex]
Thus,
The first equation should be multiplied by the constant 5
Learn more about system of linear equations here:
https://brainly.com/question/13722693
