![\bf \begin{cases} \boxed{y}=-2x\\\\ -x-y=4 \end{cases} \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{since we know what \boxed{y} is, let's substitute it in the 2nd equation}}{-x-\left( \boxed{-2x} \right)=4\implies -x+2x=4\implies x=4} \\\\[-0.35em] ~\dotfill\\\\ y=-2x\implies y=-2(4)\implies y=-8 \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill (4,-8)~\hfill](/tpl/images/0016/0499/47055.png)
Can someone explain how to do this ?
...
Answers: 1
Another question on Mathematics
Mathematics, 21.06.2019 17:00
Acertain population of bacteria demonstrates exponential growth doubles in size every 4 days. how long will it take the population to triple in size?
Answers: 1
Mathematics, 21.06.2019 17:30
Tom wants to order tickets online so that he and three of his friends can go to a water park the cost of the tickets is 16.00 per person there is also a 2.50 one-time service fee for ordering tickets online write an expression in term of n that represents the cost for n ordering tickets online
Answers: 1
Mathematics, 21.06.2019 22:30
What fraction is equivalent to 0.46464646ยทยทยท a. 46โ99 b. 46โ999 c. 46โ100 d. 23โ50
Answers: 1
Mathematics, 22.06.2019 05:00
Hello i need with my math homework i don't understand can someone explain how this works
Answers: 3
You know the right answer?
Questions
History, 20.09.2019 20:00
Mathematics, 20.09.2019 20:00
Computers and Technology, 20.09.2019 20:00
Mathematics, 20.09.2019 20:00
Mathematics, 20.09.2019 20:00
Mathematics, 20.09.2019 20:00
Chemistry, 20.09.2019 20:00
Social Studies, 20.09.2019 20:00
Mathematics, 20.09.2019 20:00
Computers and Technology, 20.09.2019 20:00
