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### Course: Pre-algebra > Unit 6

Lesson 4: 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?

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

## Let's try some practice problems!

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- I don't understand how any of this works.(26 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.(61 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(24 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.(14 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!(7 votes)

- I don't get why 2t over t as t increases stays the same, why? I just don't get it.(15 votes)
- ur adding/multiplying/subtracting/dividing the same thing on both sides of the fraction so it wont change no matter wut(4 votes)

- Can any of you guys can help me with this? I am really struggling with this topic. Please help...(13 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.(5 votes)

- why does it decrease if your added k + 35 as k decreases?(8 votes)
- Remember "death to the world?" and also it is because you are adding less to 35. Ex. if k = 5 k+35=40, but if k decreases (4) 35+4=39, so it decreased by 1.(14 votes)

- Why does it stay the same? It would decrease because it's a division problem. How does it stay the same?(7 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!(8 votes)

- whats 93 times x if x is 63?(5 votes)
- So you don't have to do it yourself (just because you seem to be struggling) the answer is 5,859(5 votes)

- I don't understand why: What happens to the value of the expression 2t/t as t increases? And the answer is: It stays the same. How is that possible? I don't get it.(5 votes)
- Because you are doing the same thing to both sides so the unknown cancels out both sides(4 votes)