Q. Solve the system of equations by elimination method.−3x−5y=−75x+3y=17
Write Equations: Write down the system of equations.We have the following system of equations:−3x−5y=−75x+3y=17We need to eliminate one of the variables by combining the equations.
Multiply Equations: Multiply each equation by a number that will make the coefficients of one of the variables opposites.To eliminate y, we can multiply the first equation by 3 and the second equation by 5, which will give us coefficients of −15 and 15 for y, respectively.3(−3x−5y)=3(−7)5(5x+3y)=5(17)
Combine Equations: Perform the multiplication from Step 2.−9x−15y=−2125x+15y=85Now we can add these two equations together to eliminate y.
Add Equations: Add the two equations together to eliminate y.(−9x−15y)+(25x+15y)=−21+85−9x+25x=6416x=64
Solve for x: Solve for x.Divide both sides of the equation by 16 to find the value of x.1616x=1664x=4
Substitute for y: Substitute the value of x back into one of the original equations to solve for y. We can use the first equation −3x−5y=−7. Substitute x=4 into the equation: −3(4)−5y=−7−12−5y=−7
Solve for y: Solve for y.Add 12 to both sides of the equation to isolate the term with y.−5y=−7+12−5y=5Now, divide both sides by −5 to find the value of y.y=5/−5y=−1