Anonymous
Anonymous asked in Science & MathematicsMathematics · 8 years ago

ALGERBA 1 HELP? 10 points?

Okay this is solving QUADRATIC equations but I'm so stuck in these problems and I need help

Solve each equation.

25x^2=81

And

X^2=16x-28

And

3a^2+10a= -8

2 Answers

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  • 7 years ago
    Favorite Answer

    25x^2 = 81

    x^2 = 81/25

    x = +9/5 OR -9/5 ANSWER

    2) x^2 -16x +28 = 0

    ( x-14) ( x-2) = 0

    x = 14 OR 2 ANSWER

    3) 3a^2 +10a +8 = 0

    3a^2 +6a +4a +8 = 0

    3a ( a +2) +4 (a+2) = 0

    ( 3a +4) ( a+2) = 0

    a = -4/3 OR -2 ANSWER

  • The last one is a quadratic (in the form of ax^2 + bx + c), so just use the quadratic formula of x = -b +/- square root (b^2 - 4ac) ALL over 2a.

    3a^2 + 10a = -8

    3a^2 + 10a + 8 = 0

    a = (-10 +/- [square root (10^2 - 4*3*8)])/2*3 (Quadratic formula)

    a = (-10 +/- [square root (100 - 96)])/6

    a = (-10 +/- 2)/6

    a = -8/6 OR a = -12/6

    a = -4/3 OR a = -2

    .

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