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0.4 x + 0.3 y = 1.7, 0.7 x - 0....

` 0.4 x + 0.3 y = 1.7`,
` 0.7 x - 0.2 y = 0.8`

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To solve the given system of linear equations: 1. **Equations to Solve:** \[ 0.4x + 0.3y = 1.7 \quad \text{(1)} \] \[ 0.7x - 0.2y = 0.8 \quad \text{(2)} \] 2. **Multiply to Eliminate Decimals:** To simplify the calculations, we can multiply both equations by 10 to eliminate the decimals: \[ 10(0.4x + 0.3y) = 10(1.7) \implies 4x + 3y = 17 \quad \text{(3)} \] \[ 10(0.7x - 0.2y) = 10(0.8) \implies 7x - 2y = 8 \quad \text{(4)} \] 3. **Multiply Equations to Align Coefficients:** Next, we will multiply equation (3) by 2 and equation (4) by 3 to align the coefficients of \(y\): \[ 2(4x + 3y) = 2(17) \implies 8x + 6y = 34 \quad \text{(5)} \] \[ 3(7x - 2y) = 3(8) \implies 21x - 6y = 24 \quad \text{(6)} \] 4. **Add the Two New Equations:** Now, we can add equations (5) and (6): \[ (8x + 6y) + (21x - 6y) = 34 + 24 \] This simplifies to: \[ 29x = 58 \] 5. **Solve for \(x\):** Divide both sides by 29: \[ x = \frac{58}{29} = 2 \] 6. **Substitute \(x\) Back to Find \(y\):** Now, substitute \(x = 2\) back into one of the original equations. We can use equation (4): \[ 7(2) - 2y = 8 \] Simplifying gives: \[ 14 - 2y = 8 \] Rearranging gives: \[ -2y = 8 - 14 \implies -2y = -6 \] Dividing by -2: \[ y = \frac{-6}{-2} = 3 \] 7. **Final Solution:** The solution to the system of equations is: \[ x = 2, \quad y = 3 \]

To solve the given system of linear equations: 1. **Equations to Solve:** \[ 0.4x + 0.3y = 1.7 \quad \text{(1)} \] \[ 0.7x - 0.2y = 0.8 \quad \text{(2)} ...
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{:(0.4x + 0.3y = 1.7),(0.7x - 0.2y = 0.8):}

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Knowledge Check

  • The solution of the system of linear equations 0.41 + 0.3y = 1.7 and 0.7x – 0.2y = 0.8, is

    A
    `x = 3, y = 2`
    B
    `x = 2, y = -3`
    C
    `X=2, y=3`
    D
    None of these
  • The equaiton of the lines representing the sides of a triangle are 3x - 4y =0 , x+y=0 and 2x - 3y = 7 . The line 3x + 2y = 0 always passes through the

    A
    incentre
    B
    centrroid
    C
    circumcentre
    D
    orthocenter
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