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3 years ago

The temperature started at −20 ∘F then rose by 12 ∘F. Write and then evaluate an expression for the current temperature.

Mathematics

2 answers:

Mashcka [7]3 years ago

3 0

Answer:

-32°F

Step-by-step explanation:

current temperature = -20°F-12°F

= - 32°F

I am not sure if its correct

zii3 years ago

0 0

exprisoon for -20 and 12

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Last year 63 inches of rain fell oaktown. In pine city 7 inches of rain fell last year. Write and solve equation to find how man

Nonamiya [84]

Answer:

Oaktown had 9 times more inches of rain than Pine City did.

Step-by-step explanation:

63 divided by 7 = 9.

Very simple problem. Glad to help.

4 0

3 years ago

Look at the system of equations below.

Annette [7]

Answer:

Substitution and graphing are less efficient methods than elimination for this system as there is extra amount of steps we have to take to solve the same system of equations - hence time consuming and a margin or error may happen. Therefore, elimination is the suitable method for solving this system.

Step-by-step explanation:

Let us consider the system of equation below.

$4x-5y=3$

$3x+5y=13$

Elimination method sounds the most appropriate option to solve the given system of equations as we can easily sort out an equation in one variable x in minimal steps by just adding the both equations as the y-coefficient in the first equation is the opposite of the y-coefficient in the second equation, and we can determine an equation in one variable x.

Adding both equations will eliminate the y-variable and we can easily sort out the value of x from the resulting equation.

As the given system of equation

$4x-5y=3$ $......[1]$

$3x+5y=13$ $......[2]$

Adding Equation 1 and Equation 2

$4x-5y+3x+5y=3+13$

$7x=16$

$x=$ $\frac{16}{7}$

Putting $x=$ $\frac{16}{7}$ in Equation [1]

$4x-5y=3$ $......[1]$

$y=$ $\frac{43}{35}$

Although substitution or graphing methods can also be used to bring the solution of the given system of equations, but using substitution or graphing method can be sometimes cumbersome or time-consuming as it would have to take some additional steps to solve the system.

For example, if we would have to use the substitution methods to solve the given system of equations, first we would have to solve one of the equations by choosing one of the equation for one of the chosen variables and then putting this back into the other equation, and solve for the other, and then back-solving for the first variable.

As the given system of equation

$4x-5y=3$ $......[1]$

$3x+5y=13$ $......[2]$

Solving the equation 2 for x variable

$3x=13-5y$

$x=\frac{13-5y}{3}$

Plugging $x=\frac{13-5y}{3}$ in equation [1]

$4(\frac{13-5y}{3}) -5y=3$

$y = \frac{43}{35}$

Putting $y = \frac{43}{35}$ in Equation 2

$3x+5y=13$ $......[2]$

$x = \frac{16}{7}$

So, you can figure out, we have to make additional steps when we use substitution method to solve this system of equations.

Similarly, using graphing method, it would take a certain time before we identify the solution of the system.

Hence, from all the discussion and analysis we did, we can safely say that substitution and graphing are less efficient methods than elimination for this system as there is extra amount of steps we have to take to solve the same system of equations - hence time consuming and a margin or error may happen.

Therefore, we agree with the student argument that Elimination is the best method for solving this system because the y-coefficient in the first equation is the opposite of the y-coefficient in the second equation.

Keywords: substitution method, system of equations, elimination method

Lear more about elimination method of solving the system of equation from brainly.com/question/12938655

#learnwithBrainly

4 0

4 years ago

Convert 7 months into days.

IgorC [24]

Answer:

212 days are in 7 months

7 0

3 years ago

Read 2 more answers

Rewrite 1/5:1/2 as a unit rate

yulyashka [42]

Hey there! I'm happy to help!

The unit rate is how much stuff there is per 1 unit. All ratios can be rewritten as fractions, this one could be 0.2/0.5. The word per means divide, and fractions are basically dividing. So, we want the denominator to be 1.

To get 0.5 to 1, we multiply by 2. So, we will multiply the fraction by 2/2.

0.2/0.5(2/2)=0.4/1

Therefore, the unit rate is 0.4/1 or 0.4:1 or 0.4 per 1.

Have a wonderful day! :D

4 0

3 years ago

1. A magazine advertise its $12 annual subscription price 70% off the newsstand price. What is the number of dollars per year a

ollegr [7]

1. $17.14

12 represents 70%
x represents 100%

rule of three

Price Percentage
+12 70-
-x 100+

$x= \frac{12*100}{70} 
 \\ \\
x= \frac{12*10}{7} 
 \\ \\ x=17.14$

3 0

3 years ago