Which of these strategies would eliminate a variable in the system of equations?{8x+5y=−7−7x+6y=−4Choose 1 answers:(A) Multiply the top equation by 6 , multiply the bottom equation by −5 , then add the equations.(B) Multiply the top equation by 7 , then add the equations.(C) Multiply the bottom equation by 8 , then add the equations.
Q. Which of these strategies would eliminate a variable in the system of equations?{8x+5y=−7−7x+6y=−4Choose 1 answers:(A) Multiply the top equation by 6 , multiply the bottom equation by −5 , then add the equations.(B) Multiply the top equation by 7 , then add the equations.(C) Multiply the bottom equation by 8 , then add the equations.
Analyze strategies: Analyze the given strategies to determine which one will eliminate a variable.We have the system of equations:8x+5y=−7−7x+6y=−4We need to find a strategy that will result in the coefficients of either x or y being opposites so that when we add the equations, one of the variables will be eliminated.
Evaluate option A: Evaluate option A.Option A suggests multiplying the top equation by 6 and the bottom equation by −5, then adding the equations.Let's perform the multiplication to see if it will eliminate a variable:(8x+5y)×6=48x+30y(−7x+6y)×−5=35x−30yNow, let's add the equations to see if a variable is eliminated:48x+30y+35x−30y=0x+0y, which simplifies to 83x=0This does not eliminate a variable.
Evaluate option B: Evaluate option B.Option B suggests multiplying the top equation by 7, then adding the equations.Let's perform the multiplication to see if it will eliminate a variable:(8x+5y)×7=56x+35yNow, let's add the equations to see if a variable is eliminated:56x+35y+(−7x+6y)=49x+41yThis does not eliminate a variable.
Evaluate option C: Evaluate option C.Option C suggests multiplying the bottom equation by 8, then adding the equations.Let's perform the multiplication to see if it will eliminate a variable:(−7x+6y)×8=−56x+48yNow, let's add the equations to see if a variable is eliminated:8x+5y+(−56x+48y)=−48x+53yThis does not eliminate a variable.
Determine correct strategy: Determine the correct strategy.Upon evaluating all options, we see that option A is the correct strategy because it results in the y terms being opposites (30y and −30y), which will eliminate the y variable when the equations are added together.
More problems from Solve a system of equations using elimination