The first problem you worked was this one: 5[4 + 3(2x − 1)]. Which expression is equivalent
to 5[4 + 3(2x − 1)]?
A 70x − 35
B 30x + 5
C 70x − 1
D 35x
The first thing to do is store a random number into the calculator. When you are double checking a problem check to see what variables are used. If there is one variable, you need to only store one number. If there are two variables, you need to store two numbers.
How do you decide what number to try? Do not use 0, 1, or 2. If you pick a random number to store, you might just pick 10. Type in the number 10, press STO, press x, T θ, n button (or ALPHA x), and press ENTER.
NOTE: The bracket keys on the calculator do NOT mean the brackets in the problem. Use another set of parentheses where you see brackets. Type in the original expression using two sets of parentheses.
305 is the magic number!
So if you think B is right, type in choice B as it appears in the problem.
305 is the magic number!
Looks like B is correct. However, it’s possible we might get 305 for another answer choice. If that happens we need to try a number other than 10.
Type in A, C, and D to confirm they are incorrect.
The only answer choice that gives the magic number is B!
What if you do not want to use the STORE button? You can simply substitute 10 into the expressions and check your answer.
305 is still the magic number.
In your notes, answer these questions.