Need help with algebra Please!!

1. Simplify. 5–1(3–2) (1 point)
A)45
B)1/45
C)15^–3
D)15^2 ----------------

2. Simplify. mn^-4/p^0q^-2 (1 point)
A)mq^2/n^4
B)mp/n^4
C)mn^4q^2p^0
D)q^2/mn^4 ----------------

3. Write in scientific notation. 0.0042 (1 point)
A)42 × 10^2
B)4.2 × 10^4
C)4.2 × 10^3 ----------------
D).42 × 10^4

4. Write in standard notation. 6.12 × 10^3 (1 point)
A)6,120 ----------------
B)612
C)61,200
D)61.2

5. Simplify. Write in scientific notation. 0.5(8 × 10^5) (1 point)
A)8 × 5^5
B)4 × 5^5
C)8 × 10^5
D)4 × 10^5 ----------------

6. Simplify. Write in scientific notation. (9 × 10^3)^2 (1 point)
A)8.1 × 10^5
B)81 × 10^4
C)81 × 10^3
D)8.1 × 10^6 ----------------

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