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2 years ago

Solve the equation x2-81 = 0.

Mathematics

2 answers:

Natasha2012 [34]2 years ago

7 0

Answer:

40.5

Step-by-step explanation:

x2 - 81 = 0 --> + 81 to both sides

2x = 81 --> divide by 2 on both sides

x = 40.5

vekshin12 years ago

5 0

Answer:

2x-81=0

2x=0+81

2x=81

x=81

x=40.5 ANSWER.

MARK ME AS A BRAINLIST PLZ.

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Clark and Lana take a 30-year home mortgage of $128,000 at 7.8%, compounded monthly. They make their regular monthly payments fo

svp [43]

Answer:

Step-by-step explanation:

From the given information:

The present value of the house = 128000

interest rate compounded monthly r = 7.8% = 0.078

number of months in a year n= 12

duration of time t = 30 years

To find their regular monthly payment, we have:

$PV = P \begin {bmatrix} \dfrac{1 - (1 + \dfrac{r}{n})^{-nt}}{\dfrac{r}{n}} \end {bmatrix}$

$128000 = P \begin {bmatrix} \dfrac{1 - (1 + \dfrac{0.078}{12})^{- 12*30}}{\dfrac{0.078}{12}} \end {bmatrix}$

128000 = 138.914 P

P = 128000/138.914

P = $921.433

∴ Their regular monthly payment P = $921.433

To find the unpaid balance when they begin paying the $1400.

when they begin the payment ,

t = 30 year - 5years

t= 25 years

$PV= 921.433 \begin {bmatrix} \dfrac{1 - (1 - \dfrac{0.078}{12})^{25*30}}{\dfrac{0.078}{12}} \end {bmatrix}$

PV = $121718.2714

C) In order to estimate how many payments of $1400 it will take to pay off the loan, we have:

$121718.2714 = \begin {bmatrix} \dfrac{1300 (1 - \dfrac{12.078}{12}))^{-nt}}{\dfrac{0.078}{12}} \end {bmatrix}$

$121718.2714 = 200000 \begin {bmatrix} (1 - \dfrac{12.078}{12}))^{-nt} \end {bmatrix}$

$\dfrac{121718.2714}{200000 } = \begin {bmatrix} (1 - \dfrac{12.078}{12}))^{-nt} \end {bmatrix}$

$0.60859 = \begin {bmatrix} (1 - \dfrac{12}{12.078}))^{nt} \end {bmatrix}$

$0.60859 = (0.006458)^{nt}$

$nt = \dfrac{0.60859}{0.006458}$

nt = 94.238 payments is required to pay off the loan.

How much interest will they save by paying the loan using the number of payments from part (c)?

The total amount of interest payed on $921.433 = 921.433 × 30(12) years

= 331715.88

The total amount paid using 921.433 and 1300 = (921.433 × 60 )+( 1300 + 94.238)

= 177795.38

The amount of interest saved = 331715.88 - 177795.38

The amount of interest saved = $153920.5

6 0

3 years ago

Least common multiple of 70, 60, and 50

goldenfox [79]

70 = 7 x 2 x 5
60 = 2² x 3 x 5
50 = 2 x 5²

LCM = 2 x 3 x 5 x 7 = 210

Answer: LCM = 210

3 0

3 years ago

If sin^2(x) - 2sin(x) = 2, then sin(x) = _____.

alekssr [168]

Let z = sin(x).
.. z^2 -2z = 2
.. z^2 -2z +1 = 3
.. (z -1)² = 3
.. z -1 = ±√3
.. z = 1 -√3 . . . . . the positive solution is extraneous

sin(x) = 1 -√3

3 0

3 years ago

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Lady bird [3.3K]

B. the line is going up so it’s going to be positive not negative. the b value is gonna be negative 1 instead of positive because it crosses the y axis closer to -1 than it does 1

4 0

3 years ago

Country A, Country B, and Country C won a total of 130 medals. Country B won 10 more medals than Country C. Country A won 38 m

snow_lady [41]

Answer:

Country A = 84

Country B = 28

Country C = 18

Step-by-step explanation:

Country A, Country B, and Country C won a total of 130 medals;

A + B + C = 130 ......1

Country B won 10 more medals than Country C;

B = C + 10 .......2

Country A won 38 more medals than the total amount won by the other two;

A = B + C + 38 ........3

Substituting equation 3 to 1;

(B+C+38) + B+C = 130

2B + 2C + 38 = 130 .......4

Substituting equation 2 into 4;

2(C+10) + 2C + 38 = 130

4C + 58 = 130

4C = 130-58 = 72

C = 72/4 = 18

B = C + 10 = 18 + 10 = 28

A = B + C + 38 = 18 + 28 + 38 = 84

Country A = 84

Country B = 28

Country C = 18

8 0

3 years ago