March 4, 2010 Math 201 OBJECTIVE: Students will be able to solve and explain two-step equations involving whole numbers. AIM: How do we use inverse operations to isolate the variable on one side of the equal sign? STANDARDS: 6.A.4 PRIOR KNOWLEDGE: What number can I add to 5 to make it zero? What number can I add to -7 to make it zero? What number will divide 4 to make it 1? What number can I multiply ½ to make it 1?

MINILESSON: Solving an equation means finding the number that replaces the variable in the equation Look at n + 3 = 5 You can solve this equation mentally by asking “What number added to 3 equals 5?” But what if the equation is 8n – 26 = 70 You might need a strategy to simplify the computation

But what if the equation is 8n – 26 = 70 You might need a strategy to simplify the computation BEST WAY GET THE VARIABLE BY ITSELF Example 8n – 26 = 70 If we want to get the n all by itself on the left side, we first look at numbers without a variable on the same side.

8n – 26 = 70 We ask “What inverse operation can I use to cancel that number out and get rid of it?” REMEMBER, if I do something to the left side of the equal sign, I have to do the same thing on the right side That leaves me

What is going on with the variable now? So, what inverse operation can we use to get rid of it? REMEMBER to do the same thing to the other side Now, we finally isolated the variable

Example 4y – 6 = 30 Strategy: Isolate the variable Step 1: Get rid of constants by doing the inverse Step 2: Get rid of coefficients by doing the inverse

You try! Solve for n 5n + 15 = 55 Strategy: Isolate the variable Step 1: Get rid of constants by doing the inverse Step 2: Get rid of coefficients by doing the inverse

Practice: Solve the equation 6y – 2 = 52 7a + 11 = 67

HOMEWORK due March 5 NOTE: To be completed in pencil on a separate piece of paper with your name and date on it! Solve the equation: 9a + 15 = 78 4n – 23 = 13 8z – 20 = 44 6y + 23 = 71 5n + 12 = 42