Writing and Evaluating New Equations

2.5.1 Writing and Evaluating New Equations

2.5.1 • Writing and Evaluating New Equations

Activity

Look at the following equation: 50+1=5150+1=51.

Perform each of the following operations and answer these questions: What does each resulting equation look like? Is it still a true equation?

1.

Add 12 to each side of the equation.

Compare your answer:

50+1+12=51+1250+1+12=51+12, or 63=6363=63 (or equivalent). Yes, it is still a true equation.

2.

Add 10+210+2 to the left side of the equation and 12 to the right side.

Compare your answer:

50+1+10+2=51+1250+1+10+2=51+12, or 63=6363=63 (or equivalent). Yes, it is still a true equation.

3.

Add the equation 4+3=74+3=7 to the equation 50+1=5150+1=51.

Compare your answer:

50+1+4+3=51+750+1+4+3=51+7, or 58=5858=58 (or equivalent). Yes, it is still a true equation.

4.

Write a new equation that, when added to 50+1=5150+1=51, gives a sum that is also a true equation.

Compare your answer:

Your answer may vary, but here are some samples.

  • 8+2=108+2=10. Added to the original equation gives: 50+1+8+2=51+1050+1+8+2=51+10, or 51+10=6151+10=61, or 61=6161=61.
  • a+a=2aa+a=2a. Added to the original equation gives: 50+1+a+a=51+2a50+1+a+a=51+2a, or 51+2a=51+2a51+2a=51+2a.
5.

Write a new equation that, when added to 50+1=5150+1=51, gives a sum that is a false equation.

Compare your answer:

Your answer may vary, but here are some samples

  • 3+2=73+2=7. Added to the original equation gives: 50+1+3+2=51+750+1+3+2=51+7, or 56=5856=58, which is false.
  • a+2=aa+2=a. Added to the original equation gives: 50+1+a+2=51+a50+1+a+2=51+a, or 53+a=51+a53+a=51+a, which is false.