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3 years ago

What is 2x-3=15 i need help

Mathematics

2 answers:

marusya05 [52]3 years ago

6 0

Answer:

x = 9

Step-by-step explanation:

Bingel [31]3 years ago

3 0

Answer:

x = 9

Step-by-step explanation:

2x - 3 = 15

2x = 15 + 3

2x = 18 (divide both sides by 2 to get x)

2x/2 = 18/2

x = 9

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Tommy is mounting a new television up in his living room, and the area of the television is 255 cm squares. What is the total di

solong [7]

Answer:

63.75

Step-by-step explanation:

255 divided by 4

7 0

2 years ago

Kylie buys a ceramic case priced at $75. Shipping and handling are an additional 9 2/5% of the price. How much shopping and hand

salantis [7]

$\bf \begin{array}{ccllll}
amount&\%\\
\textendash\textendash\textendash\textendash\textendash\textendash&\textendash\textendash\textendash\textendash\textendash\textendash\\
75&100\\
x&9\frac{2}{5}
\end{array}\implies \cfrac{75}{x}=\cfrac{100}{9\frac{2}{5}}\implies \cfrac{75}{x}=\cfrac{100}{\frac{9\cdot 5+2}{5}}$

$\bf \cfrac{75}{x}=\cfrac{\frac{100}{1}}{\frac{47}{5}}\implies \cfrac{75}{x}=\cfrac{100}{1}\cdot \cfrac{5}{47}\implies \cfrac{75}{x}=\cfrac{500}{47}\implies 75\cdot 47=500\cdot x
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\cfrac{3525}{500}=x\implies \cfrac{141}{20}=x\implies 7.05=x$

7 0

3 years ago

Suppose that 1 kg of Sodium-24 is reduced to 0.0156 kg in 90 hours. What is the half-life, in hours, of Sodium-24?

N76 [4]

Answer:

14.99 hours

Step-by-step explanation:

The formula for half-life is given as,

R/R' = 2ᵃ/ᵇ...................... Equation 1

Where R= Original mass of sodium-24, R' = mass of Sodium-24 after disintegration, a = Total time taken for sodium-24 to disintegrate, b = half-life of sodiun-24.

Given: R = 1 kg, R' = 0.0156 kg, a = 90 hours

Substitute into equation 1 and solve for b

1/(0.0156) = 2⁹⁰/ᵇ

Taking the log of both side

log[1/(0.0156)] = log(2⁹⁰/ᵇ)

log[1/(0.0156)] = 90/b(log2)

90/b = log[1/(0.0156)]/log2

90/b = 6.0023

b = 90/6.0023

b = 14.99 hours

b = 14.99 hours.

Hence the half-life of Sodium-24 is 14.99 hours

7 0

3 years ago

Type the correct answer in each box. Use numerals instead of words.

lubasha [3.4K]

Answer:

System A has 4 real solutions.

System B has 0 real solutions.

System C has 2 real solutions

Step-by-step explanation:

System A:

x^2 + y^2 = 17 eq(1)

y = -1/2x eq(2)

Putting value of y in eq(1)

x^2 +(-1/2x)^2 = 17

x^2 + 1/4x^2 = 17

5x^2/4 -17 =0

Using quadratic formula:

$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

a = 5/4, b =0 and c = -17

$x=\frac{-(0)\pm\sqrt{(0)^2-4(5/4)(-17)}}{2(5/4)}\\x=\frac{0\pm\sqrt{85}}{5/2}\\x=\frac{\pm\sqrt{85}}{5/2}\\x=\frac{\pm2\sqrt{85}}{5}$

Finding value of y:

y = -1/2x

$y=-1/2(\frac{\pm2\sqrt{85}}{5})$

$y=\frac{\pm\sqrt{85}}{5}$

System A has 4 real solutions.

System B

y = x^2 -7x + 10 eq(1)

y = -6x + 5 eq(2)

Putting value of y of eq(2) in eq(1)

-6x + 5 = x^2 -7x + 10

=> x^2 -7x +6x +10 -5 = 0

x^2 -x +5 = 0

Using quadratic formula:

$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

a= 1, b =-1 and c =5

$x=\frac{-(-1)\pm\sqrt{(-1)^2-4(1)(5)}}{2(1)}\\x=\frac{1\pm\sqrt{1-20}}{2}\\x=\frac{1\pm\sqrt{-19}}{2}\\x=\frac{1\pm\sqrt{19}i}{2}$

Finding value of y:

y = -6x + 5

y = -6(\frac{1\pm\sqrt{19}i}{2})+5

Since terms containing i are complex numbers, so System B has no real solutions.

System B has 0 real solutions.

System C

y = -2x^2 + 9 eq(1)

8x - y = -17 eq(2)

Putting value of y in eq(2)

8x - (-2x^2+9) = -17

8x +2x^2-9 +17 = 0

2x^2 + 8x + 8 = 0

2x^2 +4x + 4x + 8 = 0

2x (x+2) +4 (x+2) = 0

(x+2)(2x+4) =0

x+2 = 0 and 2x + 4 =0

x = -2 and 2x = -4

x =-2 and x = -2

So, x = -2

Now, finding value of y:

8x - y = -17

8(-2) - y = -17

-16 -y = -17

-y = -17 + 16

-y = -1

y = 1

So, x= -2 and y = 1

System C has 2 real solutions

4 0

3 years ago

Read 2 more answers

What is the inverse of the function f(x)= x +3

pshichka [43]

Hello,

if f(x)=y=x+3

x=y+3==>y=x-3

f^(-1) (x)=x-3 is the inverse function of f(x).

5 0

2 years ago