Solve the Linear System: 3x - 4y = 10 and 9x - 12y = 15

Question

Choose the correct answer for the following exercise:

{3x4y=109x12y=15 \begin{cases} 3x-4y=10 \\ 9x-12y=15 \end{cases}

Video Solution

Solution Steps

00:00 Solve the system of equations
00:04 Multiply by 3 so that we can isolate Y by subtraction
00:16 Now this is the system of equations
00:22 Subtract between the equations
00:34 Collect like terms
00:48 We got an illogical expression, therefore there is no solution
00:56 And this is the solution to the question

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Verify if both equations in the system are proportional.
  • Step 2: Determine if they result in a true or false statement when simplified.
  • Step 3: Conclude about the solution set based on the results.

Now, let's work through each step:
Step 1: Start with the system of equations:
{3x4y=109x12y=15\begin{cases} 3x - 4y = 10 \\ 9x - 12y = 15 \end{cases}

Step 2: Check if the second equation is a multiple of the first equation.
Divide each coefficient of the second equation by 3:
- (9x)÷3=3x(9x) \div 3 = 3x
- (12y)÷3=4y(-12y) \div 3 = -4y
- (15)÷3=5(15) \div 3 = 5
Thus, converting: {3x4y=103x4y=5\begin{cases} 3x - 4y = 10 \\ 3x - 4y = 5 \end{cases}

Step 3: We notice that while the left sides of both equations are identical, the right sides differ:
This results in a logical contradiction because 10510 \neq 5.
Thus, these lines are parallel and distinct, indicating that the system has no common points of intersection, hence no solution.

Therefore, the correct conclusion for this system of equations is No solution.

Answer

No solution