Math Destroyer Problems #14 and #15 on Practice Test 2

[wired202808]

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14. Simplify (24^x-2 y^-10) / (3x^-5 y^4), the book says the answer is 8x^5 * y^14 but I would think it should be 8x^5 * y^-14

15. If G(F(x)) = x^2 -3 and G(x) = x-3, find F(3)
The book says the answer is 9, wouldn't it be 6 because when you plug 3 into the first function you get 3^2 - 3 = 6.

Thanks for the help guys.

 

[wall1two]

14. Simplify (24^x-2 y^-10) / (3x^-5 y^4), the book says the answer is 8x^5 * y^14 but I would think it should be 8x^5 * y^-14

15. If G(F(x)) = x^2 -3 and G(x) = x-3, find F(3)
The book says the answer is 9, wouldn't it be 6 because when you plug 3 into the first function you get 3^2 - 3 = 6.

Thanks for the help guys.

the negative exponent means the reciprocal. x^-4 = 1/x^4 . the book is right.

15- the function G= x-3. if you plug F into G we get G(F)= [F]-3 = x^2 - 3
function of F just equals x^2. so 3*3 = 9