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### Unit 6: Lesson 6

Expression value intuition

# Expression value intuition

In an expression like 2x+7, the value of x can change. As the variable increases and decreases, what happens to the value of the expression?
Expression value intuitionSee video transcript

### Make sure you understand the question that Sal solved.

What happens to the value of the expression 100, minus, x as x increases?

## Let's try some practice problems!

Question 1
What happens to the value of the expression k, plus, 35 as k decreases?

## Want to join the conversation?

• Can any of you guys can help me with this? I am really struggling with this topic. Please help...
• What part of it do you not understand? If it's all of it, you should probably go to previous lessons, and study a bit more. If there's a particular section you don't understand, or a part where it gets confusing, then we can better help you.
(1 vote)
• Why does it stay the same? It would decrease because it's a division problem. How does it stay the same?
• 2t divided by t is the same as 2 - the t on top and bottom can 'cancel' each other out (as they'll grow at the same rate).

It's a tricky one and will become more apparent as you go further through the Algebra syllabus here!
• Hi guys, I just wanted to understand the goal of this particular lesson...

I am in no way trying to be cynical, but, serious

What's the point of this?
Do we memorise this?
i.e.
"When you are subtracting a variable that it is Increasing, the expression Decreases"
"When you are dividing by a variable that decreases but still remains a whole number, the expression Increases"
"When you are dividing an increasing variable by itself, as long as it is a whole number, regardless of the value of the Variable, the answer will always be the coefficient divided by the coefficient" - in which case the usage of the variable becomes obsolete.

Thank You
• It gets you thinking about numbers, variables and their relationship. As you go further into the algebra playlist, it becomes apparent.
• i still don"t understand the concept. Hope someone can help me simplify it to my understanding
• it hard but not that much
• The video says, and the table shows, that the last problem would stay the same, yet the system markd this response as incorrect. It says that 2(t/t) decreases. Does anyone know why?
• I just tried it. I selected "stays the same" and it was marked correct.
• This makes no logical sense. If k=1 then 1+35=36, If k=2 then 2+35=37. both numbers are increasing. Yet the right answer is that it decreases. The explanation isn't really an explanation but a string of numbers. How could these numbers be decreasing? The second expression of the exercise says it decreases also but yet the expression is now 30-3a. I find there's no pattern regardless if the expression is addition or subtraction.