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To solve the exercise, we will reorder the numbers using the substitution property.
To continue, let's remember an important rule:
1. It is impossible to add or subtract numbers with variables.
That is, we cannot subtract 7 from 8X, for example...
We solve according to the order of arithmetic operations, from left to right:
Remember, these two numbers cannot be added or subtracted, so the result is:
Are the expressions the same or not?
\( 20x \)
\( 2\times10x \)
Think of variables like apples and constants like oranges - you can't add 18 apples minus 7 oranges! Variables represent unknown values, while constants are fixed numbers. They must stay separate.
First, rearrange to group like terms together: put all x-terms together and all constants together. Then combine within each group: and .
Like terms have identical variables with the same powers. In this problem, 18x, 4x, and -8x are all like terms because they're all just 'x'. The numbers -7 and -9 are like terms because they're both constants.
Remember that subtraction means adding the opposite. So becomes . Take your time with signs - they're the trickiest part!
Yes! Pick any number for x (like x = 1) and substitute it into both the original expression and your simplified answer. If you get the same result from both, you're correct!
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