Lesson 8: Communicate the Solution of an Equation

Name:

Cathy and Ahmed are trying to find the number of counters that will balance the number of lamps on the scale. Cathy knows that 12 counters weigh more than the 3 lamps. Ahmed suggested balancing the scale by adding 3 counters to the right side of the scale, along with the 3 lamps.

Order the steps that they used to solve the equation.

a.	Ahmed made sure that there was only one equal sign in each step.
b.	Cathy and Ahmed checked the solution by substituting the answer for the variable to make the equation true. 3(3) + 3 = 12.
c.	Cathy wrote the balance problem as an algebraic equation using the variable l. l represents the number of counters that equal the weight of each lamp. 3l + 3 = 12.
d.	Cathy and Ahmed solved for the variable l. 3l = 9, l = 3.
e.	Ahmed took away 3 counters from each side, and both sides balanced. 3l + 3 3 = 12 3.

What is the first step?

What is the second step?

What is the third step?

What is the fourth step?

What is the final step?

Jay wants to find the number of counters that will balance the lamps on the scale. He knows that 21 counters weigh more than the 4 lamps. He adds 1 counter along with the 4 lamps to balance the scale.

Order the steps he takes to solve the equation.

a.	Jay solves for the variable x. 4x = 20, so x = 5.
b.	Jay writes the problem as an algebraic equation using the variable x. 4x + 1 = 21.
c.	Jay substitutes the answer for the variable to check whether the equation was true. 4(5) + 1 = 21.
d.	Jay makes sure that there is only 1 equal sign in each step.
e.	Jay takes away 1 counter from each side, both sides still balance. 4x + 1 1 = 21 1.

What is the first step?

What is the second step?

What is the third step?

What is the fourth step?

10.

What is the final step?