Lisa and Katie are playing a card game, and a total of 900 points has been scored. Lisa scored 400 more points than Katie. If you let l=

l=
the number of points that Lisa scored, and k=
k=
the number of points that Katie scored, then the problem can be represented by the system:

The problem can be represented by the following system of equations:

l + k = 900

l = k + 400

We can solve this system of equations step-by-step using the method of substitution.

To represent the problem as a system of equations, we can use the following information:

1. Lisa and Katie together scored a total of 900 points.
2. Lisa scored 400 more points than Katie.

Using this information, we can form the following equations:

Equation 1: l + k = 900 (Total points scored by Lisa and Katie together is 900)

Equation 2: l = k + 400 (Lisa's score is 400 more than Katie's score)

Now, you can solve this system of equations to find the values of l and k.

L+K=900

L=K+400