What is 7 + 10(-y + 2) simplified?

Find the zeros of the function <br> f(x)= −8x^2+98

AnnZ [28]

Hello :
-8x² +98 =0
x² =98/8
x² = 49/4
x² = (7/2)²
(x= 7/2) or( x= -7/2)

5 0

3 years ago

Give the formula V=4R. How would you solve for "r"

MakcuM [25]

I would divide each side of the equation by 4.

7 0

4 years ago

A person can teyp 150 words in 5 minutes at the persons rate how many words can that person tyep in one minite

Deffense [45]

150/5=30
30 words per minute

8 0

4 years ago

5. A tank initially contains 20 lb of salt dissolved in 200-gallon of water. Starting at time t = 0, a solution containing 0.5 l

sladkih [1.3K]

Answer:

(a) Amount of salt as a function of time

$A(t)=100-80e^{-0.02t}$

(b) The time at which the amount of salt in the tank reaches 50 lb is 23.5 minutes.

(c) The amount of salt when t approaches to +inf is 100 lb.

Step-by-step explanation:

The rate of change of the amount of salt can be written as

$\frac{dA}{dt} =rate\,in\,-\,rate\,out\\\\\frac{dA}{dt}=C_i*q_i-C_o*q_o=C_i*q_i-\frac{A(t)}{V}*q_o\\\\\frac{dA}{dt}=0.5*4-\frac{A(t)}{200}*4\\\\\frac{dA}{dt} =\frac{100-A(t)}{50}=-(\frac{A(t)-100}{50})$

Then we can rearrange and integrate

$\frac{dA}{dt}= -(\frac{A(t)-100}{50})\\\\\int \frac{dA}{A-100}=-\frac{1}{50} \int dt\\\\ln(A-100)=-\frac{t}{50}+C_0\\\\ A-100=Ce^{-0.02*t}\\\\\\A(0)=20 \rightarrow 20-100=Ce^0=C\\C=-80\\\\A=100-80e^{-0.02t}$

Then we have the model of A(t) like

$A(t)=100-80e^{-0.02t}$

(b) The time at which the amount of salt reaches 50 lb is

$A(t)=100-80e^{-0.02t}=50\\\\e^{-0.02t}=(50-100)/(-80)=0.625\\\\-0.02*t=ln(0.625)=-0.47\\\\t=(-0.47)/(-0.02)=23.5$

(c) When t approaches to +infinit, the term e^(-0.02t) approaches to zero, so the amount of salt in the solution approaches to 100 lb.

7 0

3 years ago

To make 3 dinner rolls, 34 cup of flour is used. How many rolls can you make with 212 cups of flour?

mash [69]

Answer:

If 34 cups of flour was use to make 3dinner rolls. . To get the amount of cup which will make a dinner roll divide 34/3=11 approximately. So if 11.3 cups give us 1 dinner roll. To get how many dinner rolls 212 cups of flour divide 212/11.3=18.8 approximately. Or divide 212/34*3=18.8 approximately

Stepchild-by-step explanation:

6 0

3 years ago

What is 7 + 10(-y + 2) simplified?​

What is 7 + 10(-y + 2) simplified?