Which of these strategies would eliminate a variable in the system of equations?{8x+8y=28x+5y=1Choose 1 answers:(A) Add the equations.(B) Subtract the bottom equation from the top equation.(C) Multiply the top equation by 21, then subtract the bottom equation from the top equation.
Q. Which of these strategies would eliminate a variable in the system of equations?{8x+8y=28x+5y=1Choose 1 answers:(A) Add the equations.(B) Subtract the bottom equation from the top equation.(C) Multiply the top equation by 21, then subtract the bottom equation from the top equation.
Analyze the system: Analyze the system of equations to determine which strategy would eliminate a variable.We have the system of equations:8x+8y=28x+5y=1To eliminate a variable, we need to make the coefficients of that variable the same with opposite signs or identical so that they cancel each other out when we add or subtract the equations.
Evaluate first strategy: Evaluate the given strategies to see which one will eliminate a variable.The first strategy is to add the equations. If we add them as they are, we get:(8x+8y)+(8x+5y)=2+116x+13y=3This does not eliminate any variable.
Evaluate second strategy: Evaluate the second strategy, which is to subtract the bottom equation from the top equation.(8x+8y)−(8x+5y)=2−18x+8y−8x−5y=1The 8x terms cancel out, leaving us with:3y=1This strategy eliminates the variable x.
Evaluate third strategy: Evaluate the third strategy, which is to multiply the top equation by (1)/(2), then subtract the bottom equation from the top equation.First, we multiply the top equation by (1)/(2):(1/2)×(8x+8y)=(1/2)×24x+4y=1Now we subtract the bottom equation from this new equation:(4x+4y)−(8x+5y)=1−14x+4y−8x−5y=0−4x−y=0This strategy does not eliminate a variable immediately, and it also results in a math error because the subtraction was not performed correctly.
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