How do you substitute 5x+4y=0 , x-y=9

Steps:
1.Change x-y=9 into slope-intercept form.
Subtract x on both sides
-y=-x + 9
Divide everything by -1
Y= x-9
2. Now substitute the y in 5x + 4y=0 for x-9
5x + 4(x-9)= 0
5x + 4x-36=0
3. Now combine like terms
9x-36=0
4. Add 36 on both sides
9x= 36
5. Divide each side by 9
6. X= 4
7. Now substitute the x in x-y=9 for 4
4-y=9
8. Subtract 4 on both sides
-y= 5
9. Divide everything by -1
10. Y= -5
11. Your answer is x= 4 and Y= -5 or (4,-5)

No, this coil will not be enough to complete the job.

Step-by-step explanation:

Given:

Alex the electrician needs 34 yards of wire to complete a job. He has a coil of wiring in his workshop. The coil of wire is 18 inches in diameter and it's made up of 21 circles of wire.

Now, to find will the coil be enough to complete the job.

So, we find the radius:

Radius (r) =

Now, to get the circumference of wire by putting formula:

Let pi=3.14

So, there are 21 circles of wire in the coil.

Thus, the circumference of the whole wire:

As, Alex needs 34 yards of wire to complete a job.

So, by conversion factor we convert the yards of wire Alex need to inches:

1 yard = 36 inches.

34 yards = 36 × 34 = 1224 inches.

Thus, Alex need 1224 inches of wire.

And, the coil of wire in his workshop is 1186.92 inches which is less than the wire he needs.

Hence, the coil of wire is not enough to complete the job.

Therefore, this coil will not be enough to complete the job.