A diamond today cost ten dollars more than twice what it cost last year. The sum of the cost (last year and this year) is $2500. What is the cost of last year diamond? What are the reasonable domain and range?

The cost of the diamond last year is x = $ 830

Step-by-step explanation:

Let the cost of diamond last year = x

the cost of diamond present year = y

Given that diamond today cost ten dollars more than twice what it cost last year.

⇒ y = 2 x + 10   (1)

The sum of the cost (last year and this year) is  = $ 2500

⇒ x + y = $ 2500 (2)

Put the value of y in equation (2) from equation (1), we get

⇒ 2 x + 10 + x = $ 2500

⇒ 3 x = 2490

⇒ x = $ 830

& y = 2500 - 830

⇒ y = $ 1670

Therefore the cost of the diamond last year is x = $ 830

5x+40

5(x + 8)

7x - 49

7(x - 7)

18x + 9

9(2x + 1)

15x - 10

5(3x - 2)

step-by-step explanation:

for number one all you have to do is factor 5 out of 5x + 40

for number 2 factor 7 out of 7x - 49

for number three factor 9 out of 18x + 9

for number four factor 5 out of 15x - 10

hello i am doing good for you that it's summer in your country or state ; )

btw in my country we just have sun and rain as (because i live in the caribbean lol)

also, thx a lot for the points : )