It's because any number multiplied by 0 equals 0. We could put any 2 numbers other than 2.7 and 2.8 yet still get both sides of the equation = - 5.9 but the 2 sides are obviously not equal.
To do the test correctly he can use any number except 0.
Sample Response: The coefficients of x are different in the expressions, but the constant values are the same. Zero times any value is zero, so both expressions will be equal to –5.9. If Ryan tried any other number, he would see that the expressions are not equivalent.
