Question

Ryan is trying to determine whether 2.7x – 5.9 is equivalent to 2.8x – 5.9. To test this, he substitutes 0 for x into both expressions. Explain why this will not give him the correct answer.

Answer 1

Anything times 0 is and always will be zero

Answer 2

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.