Let's practice! If 3x - y = 15 and x + 3y = 3, then the result of x - 2y =
Answers
Answer: the value of x - 2y is 6
Step-by-step explanation:
Let's practice! If 3x - y = 15 and x + 3y = 3, then the result of x - 2y =
For problems like this, we can use the Two Variable Linear Equation System (SPLDV) method. There are 4 ways, 2 of which are elimination which is eliminating one variable, and the other is substitution.
Discussion
The mathematical model
3x - y = 15
x + 3y = 3
The first step that we do is make the coefficient of one variable the same so that it can be eliminated. We choose the variable x.
The first equation multiplied by 1, while the second equation multiplied by 3
3x - y = 15 | x1 |
x + 3y = 3 | x3 |
So we eliminate the results
3x - y = 15
3x + 9y = 9
----------------- -
-10y = 6
y = 6 / (- 10)
y = -3/5
Next, we substitute the y value for one of the equations to find the value of x.
3x - y = 15
3x = 15 + y
3x = 15-3/5
3x = 75/5 - 3/5
x = 72/5: 3/1
x = 72/5 x 1/3
x = 24/5
Enter the value of x and y to the value in question
x - 2y
= 24/5 - 2 (-3/5)
= 24/5 + 6/5
= 30/5
= 6
So, the value of x - 2y is 6
Hope it helps ✌
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