Q. Solve the system of equations.−2x+9y=11−5x+2y=−34x=□y=□
Multiply second equation: Multiply the second equation by a number that will allow us to eliminate one of the variables when added to the first equation. We can multiply the second equation by 2 to eliminate 'y' when added to the first equation.−2(−5x+2y)=−2(−34)10x−4y=68
Add new equation to eliminate 'y': Add the new equation from Step 1 to the first equation to eliminate 'y'.(−2x+9y)+(10x−4y)=11+68−2x+10x+9y−4y=798x+5y=79
Solve for 'x': Solve the new equation from Step 2 for 'x'.8x+5y=79Since we don't have a value for 'y' yet, we can't solve for 'x' directly. We need to find the value of 'y' first using the original equations.
Multiply first equation: Multiply the first equation by a number that will allow us to eliminate 'x' when added to the second equation. We can multiply the first equation by 5 to eliminate 'x' when added to the second equation.5(−2x+9y)=5(11)−10x+45y=55
Add new equation to eliminate 'x': Add the new equation from Step 4 to the second equation to eliminate 'x'.(−10x+45y)+(−5x+2y)=55−34−10x−5x+45y+2y=21−15x+47y=21
Solve for 'y': Solve the new equation from Step 5 for 'y'.−15x+47y=21We made a mistake in the previous step; we should have added the equations to eliminate 'x', not subtracted them. Let's correct this.(−10x+45y)+(−5x+2y)=55+(−34)−10x−5x+45y+2y=55−34−15x+47y=21This is still incorrect; the correct equation should be:−15x+47y=21
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