Destroyer QR #7

[LNinlove]

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I know I have made it really far...I am trying to figure this "quantum leap" out...

in the answer to #7 they multiply by -2 first...am I missing a hidden step? It has been a long time...sorry guys...

Then they go from -2x-4y+-32
to -y=-7
where the heck did x go?????/

thanks in advance....

 

[Decan]

I know I have made it really far...I am trying to figure this "quantum leap" out...

in the answer to #7 they multiply by -2 first...am I missing a hidden step? It has been a long time...sorry guys...

Then they go from -2x-4y+-32
to -y=-7
where the heck did x go?????/

thanks in advance....

They multiply equation 2 with -2 to get rid of the x

so....

(x+2y=16)-2 would turn into -2x+-4y=-32
Now add this to the first equation...

-2x-4y=-32
2x+3y=25

Since 2x and -2x cancel, you are left with -y=-7 so y =7. Now that you have y, plug it into either one of the equations to figure out x and then solve for x+y

Hope that helps!

 

[LNinlove]

Ahhhhh yes, thank you VERY much!

👍