im so lost

Question

Is 2a(5a-30) divisible by 10?

Answer 1

2a(5a-30) =1oa^2-60a   10a^2\10=a^2  2a times (-30)=-60a  -60a\10=-6a  thus the answer is a^2 -6a

Answer 2

Since you've been learning math notation...

{a|a∈Z}

Answer 3

2a(5a-30)

factor (5a-30) to get 5(a-6)

2a*5(a-6)=10a(a-6)=10(a^2-6a)

10(a^2-6a) is divisible by 10 because you can actually see the 10 multiplying (a^2-6a)

let a be any integer, then 10(a^2-6a) is an integer and a multiple of 10 because again you can actually see the

10 multiplying (a^2-6a)

 

Answer 4

Yes, but you have to distribute the 2a into the (5a-30) to get 10a^2-60a. Then divide by 10 to get a^2-6a. Then  factor the a back out to get a(a-6). Good luck!

Answer 5

A number is divisible, if the given divisor (the number that we are dividing by) divides the number with no remainder.

 

'a' in this expression means some number.

 

So, 2a(5a - 30) = 10a² - 60a using the distributive property. Now, try dividing this expression by 10:

 

(10a² - 60a)/10 = (10a²)/10 - (60a)/10 (using distributive property of division)  = a² - 6a

 

As long as a is an integer, then a² - 6a is an integer, and so the expression is divisible by 10.