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If 3x + 2y = 12 and 2x - y = 1, find the value of x.
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Multiply the second equation by 2 and add it directly to the first equation to eliminate y in one step.
System of linear equations: 3x+2y=12 and 2xтИТy=1
3x+2y=12,2xтИТy=1
Multiply the second equation by 2 and add it directly to the first equation to eliminate y in one step.
Making arithmetic or sign errors when multiplying the equations or combining terms.
Identify given equations
Note down the two simultaneous linear equations provided in the question.
3x+2y=12,2xтИТy=1
Equalize coefficients
Multiply the second equation by 2 so the coefficient of y becomes тИТ2, matching the opposite of the coefficient in the first equation.
4xтИТ2y=2
Add equations to eliminate y
Add the modified second equation to the first equation: (3x+4x)+(2yтИТ2y)=12+2.
7x=14
Solve for x
Divide both sides by 7 to isolate x.
x=714тАЛ=2
A is correct because solving the system of linear equations yields x=2.
Mastering simultaneous equations is vital for solving complex quantitative aptitude problems involving ages, mixtures, and upstream/downstream speeds.