Question

SOLVING BY UNDOINGJuan says, “I see the whole thing a different way." Here is how he explains his approach to solving 4(x + 3) = 20, which he calls “undoing": "Instead of distributing first, I want to eliminate the 4 from the left side by undoing the multiplication. a. What can Juan do to both sides of the equation to remove the 4? Why does this work? b. Solve the equation using Juan's method. Did you get the same result as David? c. Why is it appropriate for this method to be called "undoing"?

Answer 1

Juan can divide by 4, and this works because the 4 is multiplying everything in one side of the equation

`\begin{gathered} 4(x+3)=20 \\ x+3=(20)/(4)=5 \\ x=5-3=2 \end{gathered}`