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19 April, 12:56

4.9t^2-2.78t-1.15=0 what is the value of T

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  1. 19 April, 14:44
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    t = 139/490 + sqrt (75671) / 490 or t = 139/490 - sqrt (75671) / 490

    Step-by-step explanation:

    Solve for t:

    4.9 t^2 - 2.78 t - 1.15 = 0

    4.9 t^2 - 2.78 t - 1.15 = (49 t^2) / 10 - (139 t) / 50 - 23/20:

    (49 t^2) / 10 - (139 t) / 50 - 23/20 = 0

    Multiply both sides by 10/49:

    t^2 - (139 t) / 245 - 23/98 = 0

    Add 23/98 to both sides:

    t^2 - (139 t) / 245 = 23/98

    Add 19321/240100 to both sides:

    t^2 - (139 t) / 245 + 19321/240100 = 75671/240100

    Write the left hand side as a square:

    (t - 139/490) ^2 = 75671/240100

    Take the square root of both sides:

    t - 139/490 = sqrt (75671) / 490 or t - 139/490 = - sqrt (75671) / 490

    Add 139/490 to both sides:

    t = 139/490 + sqrt (75671) / 490 or t - 139/490 = - sqrt (75671) / 490

    Add 139/490 to both sides:

    Answer: t = 139/490 + sqrt (75671) / 490 or t = 139/490 - sqrt (75671) / 490
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