Solve the system ... y=3x-8 and y=-9x+4

1 answer:

7 0

1] y - 3x = -8
[2] y + 9x = 4

-3x + y = -8 9x + y = 4

Solve equation [2] for the variable y

[2] y = -9x + 4

// Plug this in for variable y in equation [1]

[1] (-9x+4) - 3x = -8
[1] - 12x = -12
// Solve equation [1] for the variable x

[1] 12x = 12

[1] x = 1
// By now we know this much :

y = -9x+4
x = 1
// Use the x value to solve for y

y = -9(1)+4 = -5

{y,x} = {-5,1}

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A hollow metal sphere has 6 cm inner and 8cm outer radii. The surface charge densities on the exterior surface is +100 nC/m2 and

natulia [17]

Answer:

<h2>Outer Electric Field is 11250 N/C.</h2><h2>Inner Electric Field is -10000 N/C.</h2>

Step-by-step explanation:

First of all, we need to read carefully and analyse the problem. As you can see, is an electrical subject, and it's given surface charge densities and radius.

So, to calculate electric fields, we need to find the proper equation to do so: $E=k\frac{q}{r^{2} }$ ; as you can see, first we need to find the charges.

We can find all charges using the surface charge densities, because it has the next relation: $p=\frac{q}{A}$ ; which indicates that charge density is the amount of charge per area. But, there's a problem, we don't have areas, so we have to calculate them first with this relation: $S=4\pi r^{2}$ ; which gives us the surface of a sphere.