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OLga [1]
3 years ago
13

If 4x^2 – bx + 81 is a perfect square trinomial. Then the value of b is

Mathematics
1 answer:
Alja [10]3 years ago
6 0

Answer:

b = 36

Step-by-step explanation:

perfect square: a² -  2ac + c²

4x²- bx + 81 = (2x)² - bx + 9² = (2x)² - 2*(2x)*(9) +9²= (2x)² - 36x +9²,

so b = 36

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What is a solution to (x + 6)(x + 2) = 60?
Elden [556K]

Answer:

Ox=4

Step-by-step explanation:

expand he equation

x²+8x-48=0

using substitution method (of the options)

4 substituted as X eliminates all an results to zero

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4 0
3 years ago
Each day that a library book is kept past its due date, a $0.30 fee is charged at midnight. Which ordered pair is a viable solut
castortr0y [4]
Each day, 30 cents are added onto the fee.

-3 days would mean -3 * 30 cents on the fee, which is -90 cents, or -0.90.
and -2.5 charges of 30 cents would be -75 cents!
...but you can't have negative days or fees, so A and B are out of the question.

4.5 charges of 30 cents IS $1.35...
...but the library charges by day, of course.

8 charges of 30 cents would be $2.40, and both of these are realistic possible numbers.

8 0
4 years ago
Read 2 more answers
A mechanic earned $983.88 for42.5 hours of work. Which is the best estimate of how much the mechanic
valentina_108 [34]

Answer:

23.15 an hour

Step-by-step explanation:

5 0
3 years ago
Your friend borrows $100 from you and promises to pay you back $109 in 8 months. What annual percentage rate (A.P.R.) are you ch
NNADVOKAT [17]

Answer:

12.0\%=0.12

Step-by-step explanation:

We have been given that your friend borrows $100 from you and promises to pay you back $109 in 8 months.

We will use simple interest formula to solve our given problem.

A=P(1+rt), where,

A = Amount after t years,

P = Principal amount,

r = Annual interest rate in decimal form,

t = Time in years.

Convert 8 months to year:

\frac{8}{12}\text{ year}=\frac{2}{3}\text{ year}

108=100(1+r*\frac{2}{3})

108=100+r*\frac{2}{3}\times 100

108-100+r*\frac{200}{3}

108-100=100-100+r*\frac{200}{3}

8=r*\frac{200}{3}

8\times \frac{3}{200}=r*\frac{200}{3}\times \frac{3}{200}

\frac{24}{200}=r

r=\frac{24}{200}

r=0.12

Convert to percent:

0.12\times 100\%=12\%

Therefore, you are charging 12% APR to you friend.

6 0
3 years ago
F(x)=-5x-4 and g(x)= -3x-2, find (f-g)(x)
Mnenie [13.5K]

Answer:

Step-by-step explanation:

(-5x-4)-(-3x-2)

-5x-4+3x+2

-2x-2

-2(x+1)

5 0
3 years ago
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