What is the solution to this system of equations? x − 2y = 15 2x + 4y = -18
Mathematics · High School · Sun Jan 24 2021
Answered on
Given the equation:
x - 2y = 15
2x + 4y = -18
Determine the solutions of the system of equation.
Solution:
In order to determine the solution, we must first solve for y for the 1st equation. To do so, transpose -2y and 15 to the opposite sides hence it must be taken to note that in transposing a number, the sign changes.
x - 2y = 15
2y = x - 15
Divide both sides by 2 in order to determine the value of y.
2y/2 = ( x - 15 ) /2
y = ½x - 15/2
Substitute the value of y, of the first equation to the 2nd equation.
2x + 4(½x + 15/2) = -18
2x + 2x + 30 = -18
4x = -18 - 30
4x = -48
Divide both sides by 4 in order to determine the value of x.
4x/4 = -48/4
x = -12
Substitute the value of x to the 1st equation.
y = (½)(-12) -15/2
y = -12/2 - 15/2
y = -27/2
Final answer:
x = -12
y = -27/2