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EleoNora [17]
3 years ago
7

Evaluate the expression: 3(a + b - 3) - 212a + b - 4) when a = 2 and b = 1

Mathematics
1 answer:
olga_2 [115]3 years ago
3 0

Answer:

417

Step-by-step explanation:

3(2+1-3)-212*2+1-4=?

3-212*2+1-4=?

3-423+1-4=?

420+1-4=?

421-4=?

417

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Solving Rational Functions Hello I'm posting again because I really need help on this any help is appreciated!!​
Greeley [361]

Answer:

x = √17 and x = -√17

Step-by-step explanation:

We have the equation:

\frac{3}{x + 4}  - \frac{1}{x + 3}  = \frac{x + 9}{(x^2 + 7x + 12)}

To solve this we need to remove the denominators.

Then we can first multiply both sides by (x + 4) to get:

\frac{3*(x + 4)}{x + 4}  - \frac{(x + 4)}{x + 3}  = \frac{(x + 9)*(x + 4)}{(x^2 + 7x + 12)}

3  - \frac{(x + 4)}{x + 3}  = \frac{(x + 9)*(x + 4)}{(x^2 + 7x + 12)}

Now we can multiply both sides by (x + 3)

3*(x + 3)  - \frac{(x + 4)*(x+3)}{x + 3}  = \frac{(x + 9)*(x + 4)*(x+3)}{(x^2 + 7x + 12)}

3*(x + 3)  - (x + 4)  = \frac{(x + 9)*(x + 4)*(x+3)}{(x^2 + 7x + 12)}

(2*x + 5)  = \frac{(x + 9)*(x + 4)*(x+3)}{(x^2 + 7x + 12)}

Now we can multiply both sides by (x^2 + 7*x + 12)

(2*x + 5)*(x^2 + 7x + 12)  = \frac{(x + 9)*(x + 4)*(x+3)}{(x^2 + 7x + 12)}*(x^2 + 7x + 12)

(2*x + 5)*(x^2 + 7x + 12)  = (x + 9)*(x + 4)*(x+3)

Now we need to solve this:

we will get

2*x^3 + 19*x^2 + 59*x + 60 =  (x^2 + 13*x + 3)*(x + 3)

2*x^3 + 19*x^2 + 59*x + 60 =  x^3 + 16*x^2 + 42*x + 9

Then we get:

2*x^3 + 19*x^2 + 59*x + 60 - (  x^3 + 16*x^2 + 42*x + 9) = 0

x^3 + 3x^2 + 17*x + 51 = 0

So now we only need to solve this.

We can see that the constant is 51.

Then one root will be a factor of 51.

The factors of -51 are:

-3 and -17

Let's try -3

p( -3) = (-3)^3 + 3*(-3)^2 + +17*(-3) + 51 = 0

Then x = -3 is one solution of the equation.

But if we look at the original equation, x = -3 will lead to a zero in one denominator, then this solution can be ignored.

This means that we can take a factor (x + 3) out, so we can rewrite our equation as:

x^3 + 3x^2 + 17*x + 51 = (x + 3)*(x^2 + 17) = 0

The other two solutions are when the other term is equal to zero.

Then the other two solutions are given by:

x = ±√17

And neither of these have problems in the denominators, so we can conclude that the solutions are:

x = √17 and x = -√17

6 0
3 years ago
Q is equidistant from the sides of ZTSR. Find mZRST. The
melisa1 [442]

9514 1404 393

Answer:

  40°

Step-by-step explanation:

Triangles QRS and QTS are congruent (HL), so the marked angles are also congruent:

  3x +2 = 4x -4

  6 = x

Then the total angle measure of angle RST is ...

  (3x +2) +(4x -4) = 7x -2 = 7(6) -2 = 40 . . . degrees

m∠RST = 40°

6 0
3 years ago
This is a scale drawing of a field. The scale is 1 in.: 10 ft. What is the actual length of the
creativ13 [48]

Answer:7ft

Step-by-step explanation:

i got it right

4 0
3 years ago
Read 2 more answers
Simplify 7b + 4 + b + 3
adelina 88 [10]

Answer:

8b + 7

Step-by-step explanation:

Add like terms.

7b + b (same as 1b) = 8b

4 + 3 = 7

8 0
3 years ago
Read 2 more answers
One gallon of paint covers 400 square feet of surface area. A typical spherical water tower holds 66,840.28 cubic feet of water.
enot [183]

Answer: There will enough to paint the outside of a typical spherical water tower.


Step-by-step explanation:

1. Solve for the radius r from the formula for calculate the volume of a sphere. as following:

V=\frac{4}{3}r^{3}\pi\\\frac{3V}{4\pi}=r^{3}\\r=\sqrt[3]{\frac{3V}{4\pi}}

2. Substitute values:

r=\sqrt[3]{\frac{3(66,840.28ft^{3})}{4\pi}}=25.17ft

3. Substitute the value of the radius into the equation fo calculate the surface area of a sphere, then you obtain that the surface area of a typical spherical water tower is:

SA=4r^{2}\pi\\SA=4(25.17ft)^{2} \pi\\SA=7,964.95ft^{2}

3. If a city has 25 gallons of paint available and one gallon of paint covers 400 square feet of surface area, you must multiply 25 by 400 square feet to know if there will be enough to paint the outside of a typical spherical water tower.

25*400ft^{2}=10,000ft^{2}

As you can see, there will enough to paint the outside of a typical spherical water tower.

7 0
3 years ago
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