50 POINTS AND BRAINLIEST TO FIRST CORRECT ANSWER

Answer:
6) Option 4
7) Option 4
8) Option 1
Step-by-step explanation:
1.31×(10^-5) = 1.131/10⁵
= 1.132/100000
= 0.00001132 (option 4)
7) 3.76×10⁴ + 5.5×10²
10²(3.76×10² + 5.5)
10²(376 + 5.5)
10²(381.5)
10²(3.815×10²)
3.815×10⁴ (option 4)
8) (4×10³)(5×10⁷)
4×10³×5×10⁷
4×5×10³×10⁷
(4×5)(10^(3+7)
(4.5)×(10^(3+7)) (option 1)
That . represents multiplication
Further simplified below:
20×10¹⁰
2.0×10¹¹