All categories

3 years ago

-28 = -7(3x + 4) +21x

Mathematics

1 answer:

Vlada [557]3 years ago

7 0

Answer:

1 Expandir.

-28=-21x-28+21x

−28=−21x−28+21x

2 Simplifica -21x-28+21x−21x−28+21x a -28−28.

-28=-28

−28=−28

3 Ya que ambos lados son iguales, hay infinitas soluciones.

Soluciones Infinitas

Step-by-step explanation:

You might be interested in

Lina has a total of 72 blue and red marbles in a box. The probability of choosing a blue marble at random from the box is 4/9

blsea [12.9K]

Answer:

Step-by-step explanation:

probability of getting blue ball is 4/9

total cases = 72

i.e number of blue ball 32

number of red vall is 40

so extra 28 is added

3 0

3 years ago

A sporting goods store sold 30% of the baseball bats in stock. If they had 420 bats in stock, how many did they sell?

Tema [17]

Answer:they sold 126 bats

Step-by-step explanation:

30/100= 3/10

3/10x420=3x42=126

6 0

3 years ago

An envelope contains $1.20 in dimes and nickels. if the dimes were quarters and the nickels were dimes, there would be $1.35 mor

balu736 [363]

The nickels in the envelope is $0. 12

<h3>How to determine the number</h3>

From the information given, we have that;

Dimes + nickels = $1. 20

1/4 dimes + dimes = $ 1. 35

Let dimes = d

Nickels = n

d + n = 1. 20 equation a

d/4 + d = 1. 35 equation b

Make 'd' subject from equation a

d = 1. 20 - n

Substitute into equation b

1. 20 - n/ 4 + 1. 20 - n = 1. 35

0. 3 - 0. 25n + 1. 20 - n = 1. 35

collect like terms

- 1. 25n = 1. 35 - 1. 5

- 1. 25 = - 0. 15

n = -0. 15/ -1. 25

n = 0. 12

Thus, the number of nickels in the envelope is $0. 12

Learn more about algebraic expressions here:

brainly.com/question/4344214

#SPJ1

7 0

2 years ago

Please help me with disss

Westkost [7]

Answer:

-4

Step-by-step explanation:

3 0

3 years ago

The concentration of dichlorodiphenyltrichloroethane (DDT - an infamous pesticide) in Lake Michigan has been declining exponenti

mojhsa [17]

Answer: A) $y=13e^{-0.1359t}$

B) H = 5.10

C) Yes

Step-by-step explanation: <u>Exponential</u> <u>Decay</u> <u>function</u> is a model that describes the reducing of an amount by a constant rate over time. Generally, it is written in the form: $y(t)=Ce^{rt}$

A) C is initial quantity, in this case, the initial concentration of DDT. To determine r, using the data given:

$y(t)=Ce^{rt}$

$2.22=13e^{13r}$

$e^{13r}=0.1708$

Using a natural logarithm property called <em>power rule:</em>

$13r=ln(0.1708)$

$r=\frac{ln(0.1708)}{13}$

$r=-0.1359$

The decay function for concentration of DDT through the years is $y(t)=13e^{-0.1359t}$

B) The value of H is calculated by $y=C(0.5)^{\frac{t}{H} }$

$2.22=13(0.5)^{\frac{13}{H} }$

$(0.5)^{\frac{13}{H} }=0.1708$

Again, using power rule for logarithm:

$\frac{13}{H} log(0.5)=log(0.1708)$

$\frac{13}{H} =\frac{log(0.1708)}{log(0.5)}$

$\frac{13}{H} =2.55$

H = 5.10

Constant H in the half-life formula is H=5.10

C) Using model $y(t)=13e^{-0.1359t}$ to determine concentration of DDT in 1995:

$y(24)=13e^{-0.1359.24}$

y(24) = 0.5

By 1995, the concentration of DDT is 0.5 ppm, so using this model is possible to reduce such amount and more of DDT.

8 0

2 years ago