Please help with 4 algebra questions!!

7. Evaluate 1/2a^4b^2 for a = –2 and b = 4. (1 point)
A)2 ----------------
B)1/2
C)3
D)4

8. Is the following statement always, never, or sometimes true?
A number raised to a negative exponent is negative. (1 point)
A)always
B)never
C)sometimes ----------------

9. Simplify (4xy^2)^3(xy)^5 (1 point)
A)64x^8y^11
B)64x^15y^30
C)12x^2y^11
D)12x^8y^11 ----------------

10. Simplify (2t^3)^3(0.4r)^2 (1 point)
A)3.2r^2
B)1.28r^2/t^-6 ----------------
C)1.28r^2/t^9
D)0.8r^2/t^-6

Respuesta :

Solution:

Law of indices

[tex]1.a ^m \times a ^n= a^{m+n} 2. \frac{a^m}{a^n}=a^{m-n}  3. a^m \times b^m=(ab)^{m}[/tex]

1.

[tex]\frac{1}{2}\times a^4\times b^2\\\\ =\frac{1}{2}\times(-2)^4\times(4)^2\\\\ =\frac{1}{2}\times2^4\times (2^2)^2\\\\ =2^{4+4-1}\\\\  2^7=128[/tex]

2.

A number raised to a negative exponent is negative.=False Statement

because, [tex]a^{-m}=\frac{1}{a^m}[/tex]

=Option (C) sometimes because [tex](-3)^{-3}=\frac{-1}{27}[/tex]

3.

[tex](4xy^2)^3(xy)^5 =4^3\times x^3 \times x^5\times y^6 \times y^5\\\\ =64 x^8 y^{11}[/tex]

=Option (A)

4.

[tex]= (2t^3)^3(0.4r)^2\\\\= 2^3\times (t^3)^3*(0.4)^2*r^2\\\\= 8 *0.16 *t^9*r^2\\\\=1.28 t^9 r^2[/tex]