Q. Solve the system of equations by elimination.x−2y−2z=73x−2y−z=−52x−2y+2z=8
Eliminate y: Add the first and third equations to eliminate y.(x−2y−2z)+(2x−2y+2z)=7+8x+2x−2y−2y−2z+2z=153x−4y=15
Prepare to eliminate z: Multiply the second equation by 2 to prepare to eliminate z with the first equation.2(3x−2y−z)=2(−5)6x−4y−2z=−10
Eliminate z: Add the modified second equation and the third equation to eliminate z.(6x−4y−2z)+(2x−2y+2z)=−10+86x+2x−4y−2y=−28x−6y=−2
Simplify: Divide the last equation by 2 to simplify.8x−6y=−24x−3y=−1
Align y terms: Now we have two equations with just x and y:3x−4y=154x−3y=−1Multiply the first equation by 3 and the second by 4 to align y terms.3(3x−4y)=3(15)4(4x−3y)=4(−1)9x−12y=4516x−12y=−4
Find x: Subtract the second equation from the first to find x. (9x−12y)−(16x−12y)=45−(−4) 9x−16x=45+4 −7x=49 x=−7
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