Systems of Linear Equations: Solve by Substitution Method (CA SS: 9.0)
p.365 (1-9:odd, 23-27:odd)
Summaries: Kyle R. (Per. 1), Shreyas T. (Per. 2), Andy H. (Per. 3), Lidia T. (Per. 4), Haley B. (Per. 5), Joseph A. (Per. 6).
10 comments:
Anonymous
said...
Today, we learned the second method of solving systems of linear equations. We reviewed the things that are common in all systems again (i.e their graphs are lines, solutions are ordered pairs etc...) The method that we learned today was the Substitution method. In this method, one must first solve for one of the two variables (y=? or x=?). Now, one must substitute the value for that variable into the other equation (if x=y+2 then y+x=8 becomes y+(y+2)=8). Now we can solve the equation. Now we must substitute the numerical value for the solved variable and put it back in the equation that is solved for one variable only. Once this equation is solved, we have an ordered pair.
For 23 it says "The sum of two numbers is 36." x+y= 36 "One number is tw more than the other." This is your secnd equation: y=x+2 "Find the number." Now that you have the two equations, you do the exact same thing as before. x+(x+2)=36 x+x+2 =36 -2 -2 2x =34 1/2(2x)=34 x =17 Now that you know what x is, plug it into the other equation. y=17+2 y=19
You do the same thing with the other ones. I hope this helps you.
Mr.Gerson, when is 1st period getting their tests back?
27 is: The difference between two numbers is 18. y-x=18 The sum of twice the smaller number and 3 times the larger is 74. 3y+2x=74 What are the numbers? Take: y-x=18 -y -y -x =-y+18 -(-x)=-(-y+18) x =y-18 Now you can plug that into the other equation. 3y+2x=74 3y+2(y-18)=74 3y+2y-36=74 5y-36=74 +36 +36 5y=110 1/5(5y)=1/5(110) y=22 Now plug this into the other equation: x=y-18 x=22-18 x=4
10 comments:
Today, we learned the second method of solving systems of linear equations. We reviewed the things that are common in all systems again (i.e their graphs are lines, solutions are ordered pairs etc...) The method that we learned today was the Substitution method. In this method, one must first solve for one of the two variables (y=? or x=?). Now, one must substitute the value for that variable into the other equation (if x=y+2 then
y+x=8 becomes y+(y+2)=8). Now we can solve the equation. Now we must substitute the numerical value for the solved variable and put it back in the equation that is solved for one variable only. Once this equation is solved, we have an ordered pair.
Shreyas T.
P.2
does anyone get 23 to 27
Mr Gerson,
Can you put up the new study island please?
Thanks!
Danielle H.
Per.3
Mr Gerson,
Can you put up the new study island please?
Thanks!
Danielle H.
Per.3
I don't get number 27...
Help?
For 23 it says "The sum of two numbers is 36."
x+y= 36
"One number is tw more than the other."
This is your secnd equation:
y=x+2
"Find the number."
Now that you have the two equations, you do the exact same thing as before.
x+(x+2)=36
x+x+2 =36
-2 -2
2x =34
1/2(2x)=34
x =17
Now that you know what x is, plug it into the other equation.
y=17+2
y=19
You do the same thing with the other ones. I hope this helps you.
Mr.Gerson, when is 1st period getting their tests back?
Saloni B.
Period 1
for #23, since one of the numbers is two more than the other number the equation would be
n+(n+2)=36
Then combine like terms and solve
get it?
Jay M
per4
Danielle, done!
27 is: The difference between two numbers is 18.
y-x=18
The sum of twice the smaller number and 3 times the larger is 74.
3y+2x=74
What are the numbers?
Take:
y-x=18
-y -y
-x =-y+18
-(-x)=-(-y+18)
x =y-18
Now you can plug that into the other equation.
3y+2x=74
3y+2(y-18)=74
3y+2y-36=74
5y-36=74
+36 +36
5y=110
1/5(5y)=1/5(110)
y=22
Now plug this into the other equation:
x=y-18
x=22-18
x=4
22,4
Hope this helps!
Saloni B.
Period 1
Thanks Saloni!
-Shivani S.
Period 4
Post a Comment