Opposite Coefficients Method for Solving Two Equations in Two Unknowns
Opposite Coefficients Method for Solving Two Equations in Two Unknowns
This Demonstration solves the system of linear equations
ax+by=c
dx+ey=f
with the opposite coefficient method.
Step 1: to eliminate , multiply the first equation by and the second by , and add the equations. Even better: multiply the first with and the second with . (Here means the least common multiple of and .)
x
d
-a
g=lcm(a,d)/a
h=-lcm(a,d)/d
lcm(a,d)
a
d
Step 2: add equations and solve a new equation for .
y
Step 3: substitute the solution for into the first given equation, and solve the new equation for .
y
x