1. a number increased by 21 is 28. find the number
2. a number decreased by 12 is equal to 30. find the number.
3. 8 less than a number is 15. fid the number
What is that
1. Let's represent the number as "x":
The number increased by 21 is 28 can be written as an equation:
x + 21 = 28
To find the value of x, we need to isolate the variable by subtracting 21 from both sides:
x = 28 - 21
Simplifying the equation gives us:
x = 7
Therefore, the number is 7.
2. Let's represent the number as "x":
The number decreased by 12 is equal to 30 can be written as an equation:
x - 12 = 30
To find the value of x, we need to isolate the variable by adding 12 to both sides:
x = 30 + 12
Simplifying the equation gives us:
x = 42
Therefore, the number is 42.
3. Let's represent the number as "x":
8 less than a number is 15 can be written as an equation:
x - 8 = 15
To find the value of x, we need to isolate the variable by adding 8 to both sides:
x = 15 + 8
Simplifying the equation gives us:
x = 23
Therefore, the number is 23.
To find the solutions to these equations, we can use algebraic expressions. Let's solve each equation step by step:
1. Equation: A number increased by 21 is equal to 28.
Let's call the number "x".
Algebraically, we can write this equation as x + 21 = 28.
To isolate the variable x, we will subtract 21 from both sides of the equation:
x + 21 - 21 = 28 - 21,
which simplifies to x = 7.
Therefore, the number is 7.
2. Equation: A number decreased by 12 is equal to 30.
Let's call the number "x".
Algebraically, we can write this equation as x - 12 = 30.
To isolate the variable x, we will add 12 to both sides of the equation:
x - 12 + 12 = 30 + 12,
which simplifies to x = 42.
Therefore, the number is 42.
3. Equation: 8 less than a number is equal to 15.
Let's call the number "x".
Algebraically, we can write this equation as x - 8 = 15.
To isolate the variable x, we will add 8 to both sides of the equation:
x - 8 + 8 = 15 + 8,
which simplifies to x = 23.
Therefore, the number is 23.
I hope this explanation helps you understand how to solve these types of equations!
Let x = the unknown number.
x + 21 = 28
x + 21 - 21 = 28 - 21
x = 7
x - 12 = 30
x = ?
How do you think you should set up the third problem?