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2 years ago

10x-5 9x+2 is my equation and I don’t know how to solve it I really need help,someone please help me solve it.

Mathematics

1 answer:

Ostrovityanka [42]2 years ago

8 0

9514 1404 393

Answer:

x = 7

Step-by-step explanation:

You solve a linear equation by putting the variable on one side of the equal sign and a constant on the other side. Here, variables and constants are on both sides of the equal sign, so you need to separate them.

The basic idea is that you add the opposite of any term you don't want. Whenever you perform any operation (like "add"), you must do it to both sides of the equation.

We observe that x-terms have coefficients of 10 and 9. We choose to add the opposite of 9x to both sides:

10 -9x -5 = 9x -9x +2

x -5 = 2 . . . . simplify

Now, we still have -5 on the left, where we don't want it. So, we add its opposite (+5) to both sides:

x -5 +5 = 2 +5

x = 7 . . . . simplify

The solution is x = 7.

_____

Additional comment

If we were to end up with an x-coefficient other than 1, we would divide both sides of the equation by that coefficient. This will leave the x-term with a coefficient of 1.

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Limit of x^2-81/x+9 As x goes toward -9

Semmy [17]

Hello,

Use the factoration

a^2 - b^2 = (a - b)(a + b)

Then,

x^2 - 81 = x^2 - 9^2

x^2 - 9^2 = ( x - 9).(x + 9)

Then,

Lim (x^2- 81) /(x+9)

= Lim (x -9)(x+9)/(x+9)

Simplity x + 9

Lim (x -9)

Now replace x = -9

Lim ( -9 -9)

Lim -18 = -18
_______________

The second method without using factorization would be to calculate the limit by the hospital rule.

Lim f(x)/g(x) = lim f(x)'/g(x)'

Where,

f(x)' and g(x)' are the derivates.

Let f(x) = x^2 -81

f(x)' = 2x + 0
f(x)' = 2x

Let g(x) = x +9

g(x)' = 1 + 0
g(x)' = 1

Then the Lim stay:

Lim (x^2 -81)/(x+9) = Lim 2x /1

Now replace x = -9

Lim 2×-9 = Lim -18

= -18

7 0

3 years ago

The cosine of 23° is equivalent to the sine of what angle

Archy [21]

Answer:

So 67 degrees is one value that we can take the sine of such that is equal to cos(23 degrees).

(There are more values since we can go around the circle from 67 degrees numerous times.)

Step-by-step explanation:

You can use a co-function identity.

The co-function of sine is cosine just like the co-function of cosine is sine.

Notice that cosine is co-(sine).

Anyways co-functions have this identity:

$\cos(90^\circ-x)=\sin(x)$

$\sin(90^\circ-x)=\cos(x)$

You can prove those drawing a right triangle.

I drew a triangle in my picture just so I can have something to reference proving both of the identities I just wrote:

The sum of the angles is 180.

So 90+x+(missing angle)=180.

Let's solve for the missing angle.

Subtract 90 on both sides:

x+(missing angle)=90

Subtract x on both sides:

(missing angle)=90-x.

So the missing angle has measurement (90-x).

So cos(90-x)=a/c

and sin(x)=a/c.

Since cos(90-x) and sin(x) have the same value of a/c, then one can conclude that cos(90-x)=sin(x).

We can do this also for cos(x) and sin(90-x).

cos(x)=b/c

sin(90-x)=b/c

This means sin(90-x)=cos(x).

So back to the problem:

cos(23)=sin(90-23)

cos(23)=sin(67)

So 67 degrees is one value that we can take the sine of such that is equal to cos(23 degrees).

6 0

3 years ago

Tom took a trip of 1,300 miles. He traveled by train at 50 miles an hour and the same number of hours by plane at 275 mph. How m

Yuri [45]

Equation:
train distance + plane distance = 1300 miles

50x + 275x = 1300
x(325) = 1300
x = 4 hours
4x2=8
---
The trip took 8 hrs.

3 0

3 years ago

Read 2 more answers

Peter is at a lumber yard. He gets 2 free boxes of nails for every 10 boards he buys. Write an expression for the number of boxe

Sati [7]

A. The number of 10-boards Peter bought is equal to n divided by 10. Then, each of the 10-boxes will get two boxes of nails. The number of boxes of nails that Peter will have after buying n boards will be,

N = (2)(n/10)

Simplifying,

 N = n/5

b. If the number of boards are 90 then,

N2 = (90/10)(2)(100 nails/box)
N2 = 1800

Answer: 1800

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3 years ago

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SCUBA diving set

lys-0071 [83]

Answer:

Step-by-step explanation:

Snorkel, mask, and flippers Slope: 2 (so in the equation, it would look like 2x).

Snorkel, mask, and flippers Y-intercept: 10 (12 - 2 = 10, which is 0 hours, possibly the initial amount)

Snorkel, mask, and flippers Slope intercept form: y = 2x + 10

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3 years ago