Thx from the website http://goodcalculators.com/ratio-calculator/
Answer:
The equivalent expression is 
Step-by-step explanation:
Additional of complex numbers:
When we add complex numbers, we add both it's real parts and imaginary parts.
In this question:

The equivalent expression is 
Answer:
0.000025
Step-by-step explanation:
PEMDAS (Exponets first.)
10^5 = 100,000
10^10 = 10,000,000,000
rewrite
2.5 x 100,000 divided by 1.0 x 10,000,000,000
PEMDAS (multiplication next.)
2.5 x (10^5) = 250,000
1.0 x (10^10) = 10,000,000,000
rewrite.
250,000 divided by 10,000,000,000 = 0.000025
0.000025
Point slope form: y1-y2=m(x1-x2)
Given the slope -4 and the set of coordinates (4,-9),
y+9=-4(x-4)
I plugged in the slope and coordinates. Since -9 came after a subtraction sign, I corrected the subtraction to addition, leaving the above point slope form equation.
I hope this helps :)