Solve the System: Tackling -y + 2/5x = 13 and 1/2y + 2x = 10

Question

Solve the above set of equations and choose the correct answer.

{y+25x=1312y+2x=10 \begin{cases} -y+\frac{2}{5}x=13 \\ \frac{1}{2}y+2x=10 \end{cases}

Video Solution

Step-by-Step Solution

To solve the given system of equations, we follow these steps:

Given equations:

  • Equation 1: y+25x=13 -y + \frac{2}{5}x = 13
  • Equation 2: 12y+2x=10 \frac{1}{2}y + 2x = 10

Step 1: Clear fractions in Equation 1 by multiplying through by 5:

5y+2x=65-5y + 2x = 65   ...(Equation 3)

Step 2: Clear fractions in Equation 2 by multiplying through by 2:

y+4x=20y + 4x = 20   ...(Equation 4)

Step 3: Align the coefficients of yy for elimination. Use Equation 3 and Equation 4, where coefficients of yy can be easily handled.

Using Equations 3 and 4:

5y+2x=65-5y + 2x = 65

y+4x=20y + 4x = 20

Step 4: Let's multiply Equation 4 by 5 to align coefficients of yy:

5y+20x=1005y + 20x = 100

Step 5: Add the resulting Equation 4 to Equation 3:

5y+2x+5y+20x=65+100-5y + 2x + 5y + 20x = 65 + 100

22x=16522x = 165

Step 6: Solve for xx:

x=16522=7.5x = \frac{165}{22} = 7.5

Step 7: Substitute x=7.5x = 7.5 back into Equation 4 to solve for yy:

y+4(7.5)=20y + 4(7.5) = 20

y+30=20y + 30 = 20

y=2030=10y = 20 - 30 = -10

Therefore, the solution is x=7.5 and y=10 x = 7.5 \text{ and } y = -10 .

The correct choice from the answer options is:

x=7.5,y=10 x=7.5,y=-10

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Answer

x=7.5,y=10 x=7.5,y=-10