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?
Make sure you understand the question that Sal solved.
What happens to the value of the expression as increases?
Let's try some practice problems!
What happens to the value of the expression as decreases?
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- I don't understand how any of this works.(5 votes)
- It's probably easier just to look at the equations rather than talk about it...
When you have 2x+7, when x is 1, the answer is 9. When x goes up to 2, the answer is 11. 11 is more than 9, so as the value of x increases, the value of the expression also increases.
But when the expression is something like 10-x, when x is 1, the answer is 9. When x is 2, the answer is 8. 8 is less than 9. So as the value of x increases, the value of the expression decreases in this case.
Hope that helps.(24 votes)
- there seems to be many quetions on this topic. let me clear up all your confusions. just fill in the problems above with a number like 1 and do it than fill it again with a number higher. if the answer u get is lower than the other one it decreases and if it is higher than it increases and if it is the same it is the last choice. i hope this helped u all. bye bye and feel free to ask any questions to me. i will gladly try to answer them. got it guys and girls(13 votes)
- I don't understand because when I was doing the math above one day I did that same kind of math and I picked increase and it was wrong then I picked decrease and it was wrong then I picked it stays the same and it was wrong I didn't understand why it didn't tell me which one was right.(9 votes)
- It was probably a mistake in the coding. I didn't have a problem with it. Try it again and see if it works!(3 votes)
- Can any of you guys can help me with this? I am really struggling with this topic. Please help...(8 votes)
- 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?(4 votes)
- 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!(4 votes)
- 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?
"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(5 votes)
- It gets you thinking about numbers, variables and their relationship. As you go further into the algebra playlist, it becomes apparent.(2 votes)
- 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.(3 votes)
- I believe you are getting confused. The question is asking what will happen to k or a when their values are changed. Number k’s value is decreasing, so the overall sum is going to get smaller. Number a is a little different though, because now we are increasing the value of the subtrahend (the number that is subtracting the minuend), so the value will decrease. The questions are a little confusing so you might need to understand what exactly the question is telling you.(2 votes)
- i still don"t understand the concept. Hope someone can help me simplify it to my understanding(3 votes)
- it hard but not that much(3 votes)
- 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?(3 votes)
- I just tried it. I selected "stays the same" and it was marked correct.(2 votes)