Sagot :
For this case, the first thing we must do is define variables.
We have then:
x: Maggie's age
y: Age of Maggie's brother
We write the system of equations that models the problem.
We have then:
[tex] y = 2x-3
x + y = 24
[/tex]
We solve the system of equations.
For this, we use substitution:
[tex] x + (2x-3) = 24
[/tex]
From here, we clear the value of x:
[tex] 3x - 3 = 24
3x = 24 + 3
3x = 27
[/tex]
[tex] x = \frac{27}{3}
x = 9
[/tex]
Answer:
Maggie is 9 years old
Maggie's age is 9
Further Explanation
One variable linear equation is an equation that has a variable and the exponent number is one.
Can be stated in the form:
[tex] \large {\boxed {\bold {ax=b}} [/tex]
or
ax + b = c,
where a, b, and c are constants, x is a variable
Whereas the two-variable linear equation is a linear equation that has 2 variables and the exponent is one
Can be stated in the form:
[tex] \large {\boxed {\bold {ax + bx = c}}} [/tex]
x, y = variable
Let Maggie's age = x
Maggie's brother = y,
In the statement of the task:
- Maggie's brother is 3 years younger than twice her age
we translate this sentence into the equation
y = 2x-3 ... equation 1
- The sum of their ages is 24
we translate this sentence into the equation
x + y = 24 ...equation 2
Both of these equations are equations that have 2 variables, so the solution can be used in 3 ways:
- 1. graph system
the solution is the intersection point of the two equations / lines.
- 2. substitution
the solution is we change one variable into another variable form of an equation, then substitutes that variable in another equation
- 3. elimination
the solution is to eliminate one variable from the equation system.
to determine the variable x we eliminate the variable y first , or vice versa.
We use the second method: substitution
we substitute equation 1 into equation 2 :
[tex]\displaystyle x+2x-3=24[/tex]
[tex]\displaystyle 3x-3=24[/tex]
[tex]\displaystyle 3x=27[/tex]
[tex]\displaystyle x=9[/tex]
So Maggie's age: [tex]\large{\boxed{\bold{9}}[/tex]
Learn more
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Keywords: variable, equation, substitution, elimination, graph, Maggie's age