# algebra

posted by on .

1)Write the expression 9n^6+7n^3-6 in quadratic form,if possible
A.9(n^3)^3+7n^3-6
B.9(n^2)^3+7(n^2)-6
C.9(n^3)^2+7(n^3)-6
D.not possible
I'm thinking C on this one but im not sure

2)solve b^4+2b^2-24=0
A.-2,-square root of 6,square root of 6,2
B.-square root of 6,2,2i,i square root of 6
C.2,2,-isquare root of 6
D.-2i,2i,- square root of 6,square root of 6

3)If f(x)= x^2+1 and g(x)= x-2,find f[g(x)]
A.x^2-4x+5
B.x^2-1
C.x^2-3
D.x^3-2x^2+x-2

4)Find the inverse of f(x)= 2x-7
=f-1(x)= x+7/2

5)Determine which pair of functions are inverses:
A.f(x)= 3x-1;g(x)= 1/3x-1
B.f(x)= 2x-5;g(x)= x+5/2
C.f(x)= 2x+2;g(x)= 2x-2
D.f(x)= 3x-8;g(x)= 1/3x+8
my answer is D or B

2.) C
3.)A
f[g(x)] = (x-2)^2 + 1
= x^2 -4x +5

4.)correct

5.) B
Follow the same procedure you did for number 4

1. C is right

2. b^4 + 2b^2 - 24 = 0
b^4 + 2b^2 = 24
b^4 + 2b^2 + 1 = 24 + 1
(b^2 + 1)^2 = 25
b^2 + 1 = ± 5
b^2 = 4 or b^2 = -6
b= ±2 or b= ±i√6

3. I got A
f[g(x)]
= f(x-2)
= (x-2)^2 + 1
= x^2 - 4x + 4 + 1
= x^2 - 4x + 5

4. ok if you include brackets as in (x+7)/2

5 ok if you include brackets as in (x+5)/2 and (1/3)(x+8)