Question

Give an example of an equation with an infinite number of solutions. Then make one change to the equation so that it has no solution

Answer 1

Two equations with infinite solutions would look the exact same. Example:
y=mx+b
y=mx+b
Example 2
y=2x+5
y=2x+5
For an equation with no solution they would have the same slope but different y intercepts. An equation with same slope and same y intercepts would have infinite solutions.