's
and
's
if they are not already aligned. For the above example, they are
aligned.
GCSE Maths Notes: Solving Simultaneous Equations Algebraically
and
at
the same time. We can solve simultaneous equations graphically, or
algebraically. I show here how to solve simultaneous equations
algebraically.
We have to line up the
's
and
's
if they are not already aligned. For the above example, they are
aligned.
The coefficients of the
's
are the same here so we can eliminate them by adding the equations
termwise.
Then substitute this value of
back
in to one of our original equations to find
.
If we choose the 1st equation then
so
The solution is
.
The equations
and
are
not aligned. We align them first.
(1)
(2)
Now we choose whether to eliminate the
's
or the
's.
I choose the first. I have to make the coefficients the same and
because they are both positive I subtract. I do 3*(1)-4*(2)
Subtraction gives
so
.
Substitute this value of y into one of the original equations to find
.
I choose (1)
so
