Answer:
The number is 4
Explanation:
* Lets revise some words in mathematics and how change them to
mathematical symbols
- More than ⇒ add (+)
- Less than ⇒ subtract (-)
- Twice ⇒ Multiplied by 2 (× 2)
- Opposite of a number ⇒ change its sign (additive inverse of it)
* Now lets solve the problem
- Nine more than the opposite of a number is three less than twice
the number
- Assume that the number is x
∴ 9 more than the opposite of x
- That means find the opposite of x and add it by 9
∵ The opposite of x is -x
∴ Nine more than the opposite of a number = -x + 9
- Three less than twice the number means 3 less than twice x
∵ The number is x
∴ Twice the number = 2 × x = 2x
∵ Three less than twice x = 2x - 3
∴ Three less than twice the number = 2x - 3
- The meaning of "is" between the two the statements is "="
∴ Nine more than the opposite of a number is three less than twice
the number is ⇒ -x + 9 = 2x - 3
* Lets solve the equation to find x
∵ -x + 9 = 2x - 3
- add x in both sides
∴ 9 = 3x - 3
- Add 3 to both sides
∴ 12 = 3x
- Divide both sides by 3
∴ x = 4
∵ x represents the number
∴ The number is 4
* Lets check the answer
9 more than opposite 4 is 3 less than twice 4
9 + (-4) = 2 × 4 - 3
9 - 4 = 8 - 3
5 = 5
The answer is right