Solve for r.......................?

r^2+3r=2

3 Answers

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  • 9 years ago
    Favorite Answer

    this can be written as

    r^2 + 3r - 2 = 0

    Now to solve this you can use the discriminat method (delta = b^2 - 4ac....)

    But if you still haven't learnt this method, then use the method of completing the square.

    r^2 + 3r + (3/2)^2 - (3.2)^2 -2 =0

    (r + 3/2)^2 = 9/4 + 2 = 17/4

    r+3/2 = +or- sqrt(17/4)

    r = + sqrt(17/4) - 3/2

    or r = - sqrt(17/4) - 3/2

    PS: this is actually a particular derivation of the discriminant method)

  • Como
    Lv 7
    9 years ago

    r ² + 3r - 2 = 0

    x = [ - b ± √ ( b ² - 4 a c ) ] / 2 a

    x = [ - 3 ± √ ( 9 + 8 ) ] / 2

    x = [ - 3 ± √ ( 17 ) ] / 2

  • 9 years ago

    r=-3.56155 or r=0.56155

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