Question

-3x + 7y = -16
-9x + 5y = 16

Part A: Create an equivalent system of equations by replacing one equation with the sum of that equation and a multiple of the other. Show the steps to do this. (6 points)

Part B: Show that the equivalent system has the same solution as the original system of equations. (4 points)

Answer 1

do you know how to do this @Mokeira ?

Answer 2

@aajugdar help

Answer 3

oh hey
you have to create two new equations

Answer 4

one by adding -3x + 7y = -16 and -9x + 5y = 16
and second
by multiplying -3x + 7y = -16 and -9x + 5y = 16

Answer 5

do i just add the x's and y's together

Answer 6

yeah

Answer 7

-3x + 7y +(-9x + 5y) = -16+16

Answer 8

ok thank and how do i do part b

Answer 9

in 2nd you have to solve original two equations as well as new equations
and you have to show that values of x and y match in both systems of equations

Answer 10

i don't know how to solve it

Answer 11

@aajugdar

Answer 12

oh?
hmm okay i will help

Answer 13

-3x + 7y = -16
-9x + 5y = 16
so you have two equations here
there are many ways to solve this
but i will tell you elimination method
okay?

Answer 14

okay

Answer 15

in elimination method what you have to do is either eliminate x compnent or y component
so in the equations
-3x + 7y = -16
-9x + 5y = 16
suppose we want to eliminate x component
now we have -3x and -9x as x components
so we multiply first equation by -3 in order to eliminate those
so you get
-3(-3x+7y=-16)
9x-21y=48

Answer 16

so now you have two equations
9x-21y=48 and
-9x + 5y = 16

Answer 17

now add these two equations
9x and -9x will be canceled
-21y+5y = -16y
48+16=64
so we get
-16y = 64
so y= 64/-16
y= -4

Answer 18

now consider this equation
-9x + 5y = 16
we know that value of y is -4
put this value in equation
-9x+5(-4) =16
-9x-20=16
-9x=36
x=-4
so you have values of x and y by elimination method
any doubts?

Answer 19

thanks a lot helped me very much!!!!!!!!!

Answer 20

you are welcome :)