Someone me my last day to turn this in! solving systems of equations by elimination 1) 5x + 2y= 21 -x - y= -9 2) 3x + 2y= -13 3x+4y= 1 3) 7x + 3y= 22 4y= 20 4) -2x + y= 10 4x - y= -14

Hello!

I'll solve the first two systems.

1)


Multiply the second equation in the system by 2 to be able to cancel out y-terms:





Now, add the equations together:


_____________




Plug 1 for x into one of the original equations to find y:







Check work by plugging your values for x and y back into both original equations:







Both are true; x = 1 and y = 8.

2)


For this system, to be able to cancel out x-terms, you can multiply either equation by -1; I'll use the bottom equation:




Now add the equations together:


_____________




Plug 7 for y into either of the original equation to solve for x:






Plug -9 for x and 7 for y into each original equation to check work:





Both are correct; x = -9 and y = 7.

Apply these steps to the last two systems and you're good to go. (: