An alloy consists of nickel, zinc, and copper in the ratio 2: 7: 9. how many pounds of nickel have to be used to create alloy that contains 4.9 lb of zinc?

We are given ratio nickel to zinc to copper = 2:7:9.

From this ratio we can see that ratio of nickel to zinc is 2:7.

Let us assume number of pounds of nickel have to be used to create alloy that contains 4.9 lb of zinc is x pounds.

So, we can setup a proportion as :

x : 4.9 =  2:7

Or

On cross multiplication, we get

7x= 4.9× 2

7x = 9.8

Dividing both sides by 7, we get

x = 1.4.

answer: yes youre right.

step-by-step explanation:

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15