Answer:
6y - 1/2y
Explanation:
So...
We need to multiply by 5y/5y to write -4 as a fraction with a common denom.
2/5y - 4 * 5y/5y + 7 - 9/10y
Simplify...
Combine the -4 and 5y/5y
2/5y + -4(5y)/5y + 7 - 9/10y
Combine the numer over the common denom
2 - 4(5y)/5y + 7 - 9/10y
Simplify the numerator by factoring 2 out of then 2 out of -4 * 5y and then 2 out of 2(1) + 2 (-2 * 5y)
2(1) - 4 * 5y/5y + 7 - 9/10y
2(1) + 2(-2 * 5y)/5y + 7 - 9/10y
2(1 - 2 * 5y)/5y + 7 - 9/10y
Now multiply -2 by 5
2(1 - 10y)/5y + 7 - 9/10y
Now we do the same 5y/5y with 7
Combine...
2(1 - 10y)/5y + 7(5y)/5y - 9/10y
Combine more.
2(1 - 10y) + 7(5y)/5y - 9/10y
Now we need to simplify more
Distributive property application
2 * 1 + 2 (-10y) + 7 * 5y/5y - 9/10y
Multiply 2 by 1
2 + 2(-10y) + 7 * 5y/5y - 9/10y
-10 by 2
2 - 20y + 7 * 5y/5y - 9/10y
Then 7 by 5
2 - 20y + 35y/5y - 9/10y
Then -20y by 35y
2 + 15y/5y - 9/10y
Now we have to multiply 2 + 15y/5y by 2/2
2+ 15y/5y * 2/2 - 9/10y
Now we write with a common denom of 10y and multiply with a factor of 1
(2 + 15y) * 2/5y * 2 - 9/10y
Multiply 2 by 5
(2 + 15y) * 2/10y - 9/10y
Combine again
(2 + 15y) * 2 - 9/10y
Simplify again with the distrib property
2 * 2 + 15y * 2 - 9/10y
Multiply 2 by 2
4 + 15y * 2 - 9/10y
Then 2 by 15
4 + 30y - 9/10y
Then subtract 9 from 4
30y - 5/10y
Factor out 5 from 30y - 5...
5(6y) -5/10y
5(6y) - 5/10y
Factor 5 out of -5
5(6y) + 5(-1)/10y
Then 5 out of 5(6y) + 5(-1)
5(6y - 1)/10y
Now we cancel more common factors which is 5 here
6y - 1/2y