Problem 71

Question

Explain how to solve a system of equations using the addition method. Use \(3 x+5 y=-2\) and \(2 x+3 y=0\) to illustrate your explanation.

Step-by-Step Solution

Verified
Answer
By using the elimination method, we have \(x = 6\) and \(y = -4\).
1Step 1: Multiply the equations to make the coefficients of y the same for elimination
The equation system given consists of \(3x + 5y = -2\) and \(2x + 3y = 0\). Multiply the first equation by 3 and the second by 5: \[3(3x + 5y) = 3(-2) \] \[5(2x + 3y) = 5(0) \]. It becomes \[9x + 15y = -6\] and \[10x + 15y = 0\]
2Step 2: Subtract one equation from the other
Once the coefficients of y are equal in both equations, they can be subtracted from each other: \[(10x + 15y) - (9x + 15y) = 0 - (-6)\] which gives \[x = 6\].
3Step 3: Substitute x into one of the original equations
Substitute \(x = 6\) into the second original equation: \[2(6) + 3y = 0\], which simplifies to \[3y = -12\] and finally, \[y = -4\].