8 - 15 means subtract the positive number 15 from 8.
8 - 15 = 8 + (-15) = -7
8 - (-15) means subtract the negative number -15 from 8.
Subtracting a negative number is the same as adding a positive number.
8 - (-15) = 8 + 15 = 23
8 - 15 = -7, and 8 - (-15) = 23. The expressions mean different operations and have different answers.
Year 1990, dolphins were 243,000
2.3% of 24300
= ( 2.3 / 100 ) * 243000
= ( 0.023 ) * 243000
= 5589
So every year, the population of dolphins decrease by 5589.
Now from 1990 to 2030 will be
= 2030 - 1990
= 40 years
Therefore, for a year = 5589 decrease
For forty years, it will be
= 40 * (5589)
= 223560 dolphins will be lost after forty years
The remaining ones
= 243000 - 223560
= 19440 dolphins will be left
X + y = 3
2x + 4y = 8
This is a system of equations. You can solve it using elimination. Start by multiplying the top equation by -2.
(x * -2) + (y * -2) = (3 * -2)
-2x - 2y = -6
Now add that and the bottom equation. This will cancel out x.
-2x - 2y = -6
+ 2x + 4y = 8
-----------------------
2y = 2
Solve for y.
2y = 2
y = 2/2
y = 1
Now plug 1 in for y in the first equation.
x + y = 3
x + 1 = 3
Solve for x.
x + 1 = 3
x = 3 - 1
x = 2
So x = 2 and y = 1.
Answer 10x - 15
Step-by-step explanation:
Because when you do the distributive property, you multiply the things in the parenthesis so 5 multiplied by 2x would be 10x and 5 multiplied by -3 would be -15. Hope this helps :)
therefore, the sum of this infinite geometric series can be calculated using the formula 
.
So, 
If 2 is the sum of this infinite series, then you'll never reach it.
