20stirltrer
29.10.2019 •
Mathematics
How many times greater sunnies wi-fi range is then lvan wi-fi range
Solved
Show answers
More tips
- S Sport Where can you play football in Moscow?...
- F Food and Cooking 10 Reasons Why You Should Avoid Giving Re-Gifts: An Informative Guide...
- S Sport How to wrap boxing hand wraps? Everything you need to know!...
- A Animals and plants 5 Tips for Taking Care of Yews to Keep Them Green and Beautiful...
- H Health and Medicine How to Calm Your Nerves? Expert Tips That Actually Work...
- O Other What is a Disk Emulsifier and How Does it Work?...
- S Sport How to Pump Your Chest Muscle? Secrets of Training...
- C Computers and Internet How to Get Rid of 3pic Infector: Everything You Need to Know...
- S Style and Beauty How to Grow Hair Faster: Real Methods and Advice...
- C Computers and Internet How to Top Up Your Skype Account Without Losing Money?...
Answers on questions: Mathematics
- M Mathematics How do you round to the nearest tenth?...
- M Mathematics If triangle tkm is similar to triangle daj whatis the measure of angle m...
- M Mathematics Andrew is at point a. a deer is 3km directly north of andrew, at point d. brian is 1.8 km due west of andrew at point b. calculate the distance between brian and the deer....
- M Mathematics The johnson family has three sons, billy, tommy, and bobby. billy is as old as tommy and bobby together. last year, tommy was twice as old as bobby was. in two years, billy will...
- M Mathematics Identify the percent of change as an increase or a decrease. 12 inches to 36 inches increase decrease find the percent of change. round to the nearest tenth of a percent if necessary....
- M Mathematics F(x)=2x-9 evaluate the function at each specified value of the independent variable and simplify...
- M Mathematics If the cos 90° = 0, then the sin 0° =...
- M Mathematics the oak tree outside omar s house grew 3 feet in 6 months. you may assume the tree grows at a constant rate. how many meters will the tree grow in 1 year? round your answer to...
- M Mathematics Marcus purchased 75 shares of stock a year after the purchase the stock the valley of the cost is $2 less per share write a multiplication expression to determine the change in...
- M Mathematics Cylinder a has a radius of 2 inches and a height of 2 inches. cylinder b has a radius of 2 inches and a height of 4 inches. calculate the surface area for both cylinders....
Ответ:
yes
step-by-step explanation:
we're asked to solve this system of equations:
\begin{aligned} 2y+7x & = -5 5y-7x & = 12 \end{aligned}
2y+7x
5y−7x
=−5
=12
we notice that the first equation has a 7x7x7, x term and the second equation has a -7x−7xminus, 7, x term. these terms will cancel if we add the equations together—that is, we'll eliminate the xxx terms:
2y+7x+ 5y−7x7y+0=−5=12=7
solving for yyy, we get:
\begin{aligned} 7y+0 & =7 7y & =7 y & =\goldd{1} \end{aligned}
7y+0
7y
y
=7
=7
=1
plugging this value back into our first equation, we solve for the other variable:
\begin{aligned} 2y+7x & = -5 2\cdot \goldd{1}+7x & = -5 2+7x& =-5 7x& =-7 x& =\blued{-1} \end{aligned}
2y+7x
2⋅1+7x
2+7x
7x
x
=−5
=−5
=−5
=−7
=−1
the solution to the system is x=\blued{-1}x=−1x, equals, start color blued, minus, 1, end color blued, y=\goldd{1}y=1y, equals, start color goldd, 1, end color goldd.
we can check our solution by plugging these values back into the the original equations. let's try the second equation:
\begin{aligned} 5y-7x & = 12 5\cdot\goldd{1}-7(\blued{-1}) & \stackrel ? = 12 5+7 & = 12 \end{aligned}
5y−7x
5⋅1−7(−1)
5+7
=12
=
?
12
=12
yes, the solution checks out.
if you feel uncertain why this process works, check out this intro video for an in-depth walkthrough.
example 2
we're asked to solve this system of equations:
\begin{aligned} -9y+4x - 20& =0 -7y+16x-80& =0 \end{aligned}
−9y+4x−20
−7y+16x−80
=0
=0
we can multiply the first equation by -4−4minus, 4 to get an equivalent equation that has a \purpled{-16x}−16xstart color purpled, minus, 16, x, end color purpled term. our new (but equivalent! ) system of equations looks like this:
\begin{aligned} 36y\purpled{-16x}+80& =0 -7y+16x-80& =0 \end{aligned}
36y−16x+80
−7y+16x−80
=0
=0
adding the equations to eliminate the xxx terms, we get:
36y−16x+80+ −7y+16x−8029y+0−0=0=0=0
solving for yyy, we get:
\begin{aligned} 29y+0 -0& =0 29y& =0 y& =\goldd 0 \end{aligned}
29y+0−0
29y
y
=0
=0
=0
plugging this value back into our first equation, we solve for the other variable:
\begin{aligned} 36y-16x+80& =0 36\cdot 0-16x+80& =0 -16x+80& =0 -16x& =-80 x& =\blued{5} \end{aligned}
36y−16x+80
36⋅0−16x+80
−16x+80
−16x
x
=0
=0
=0
=−80
=5
the solution to the system is x=\blued{5}x=5x, equals, start color blued, 5, end color blued, y=\goldd{0}y=0y, equals, start color goldd, 0, end color goldd.