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Math Help - Radical numbers

  1. #1
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    Radical numbers

    x-5-2=3
    radical sign is under the x-5.

    x= x+7+5
    radical sign is under the x+7

    Multiply

    (36 +2)(4-63)

    simplify
    (9x)^2
    Is that 3x?

    -125c^3

    Find the domain of the given function.
    F(x)=2x-3
    radical sign is under the 2x-3.

    Thank you
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  2. #2
    Behold, the power of SARDINES!
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    Quote Originally Posted by rowdy3 View Post
    x-5-2=3
    radical sign is under the x-5.


    Thank you
    The first two are similar here is the first

    \sqrt[3]{x-5}-2=3 add two to both sides

    \sqrt[3]{x-5}=5 cube both sides

    (\sqrt[3]{x-5})^3=5^3 \iff x-5=125 \iff x=130
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  3. #3
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    x= x+7+5
    Would I subtract 5 from x? That would give me -5= x+7. I would square everything (-5)^2 = x=( x+7)^2. 25= x+7. I subtract 7 and get x=18.
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  4. #4
    Behold, the power of SARDINES!
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    Quote Originally Posted by rowdy3 View Post
    x= x+7+5
    Would I subtract 5 from x? That would give me -5= x+7. I would square everything (-5)^2 = x=( x+7)^2. 25= x+7. I subtract 7 and get x=18.
    it is a little hard to follow with your formatting but

    x=\sqrt{x+7}+5 \iff x-5=\sqrt{x+7} Now square both sides

    (x-5)^2=(\sqrt{x+7})^2 \iff x^2-10x+25=x+7 collectin like terms

    x^2-11x+18=0 \iff (x-2)(x-9)=0

    So x=2 or x=9

    we need to check both solutions to see if they work

    plugging in 2 we get

    2 \overbrace{=}^{?} \sqrt{2+7}+5 \iff 2 \ne 3+5

    so 2 is Not a solution

    if you check 9 it does work so it is the only solution
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  5. #5
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    2x+3 =9
    (2x+3)^2 = (9)^2
    2x+3=81
    -3 -3
    2x/2 = 78/2
    x=39

    simplify the following radicals

    (9x)^2
    My answer is 9x

    -125c^3
    Would that be -5c
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