Edit: Sorry, just noticed it's in the wrong Categorie.
Hello, I did all this last year, but didn't memorize it Now when I look back, I dont know what to do ... I would be greatful If anyone could answer the following questions. Seeing the solution might help me understand the other questions.
- Solve the following linear systems of equations using substitution.
- y = 3x + 5
y = 2x + 4- 2x + y = 7
4x - y = 23- Solve the following linear systems using elimination. Check your solutions.
- 3x - 2y = 18
x + y = 16- 5x + 2y = 10
3x - 4y = -46- A barnyard has cows and chickens. There are 34 heads and 86 legs. If w represents the number of cows and k represents the number of chickens:
- Write a linear system of equations to model this situation.
- Solve the linear system to find the number of cows and the number of chickens in the barnyard.
- Verify your solution by providing a graphical solution. You can use a spreadsheet or Geometer's Sketchpad.
Sincerely,
Serialkisser
I see, but the second part ( y=2x+4) wasn't used ... why ?
U also wrote :
How do you know by what to multiply ?Multiply second equation by 2 and add to first equation,
3x - 2y = 18
2x + 2y = 32
---------------------------
5x = 50
---------------------------
x = 10
so, y = 6
Sorry for all that, I take online Classes :-)
Now, you see, in first eqn, coefficient of y is +2
and in second eqn, coefficient of y is -4
so, if you multiply first eqn by 2, the coefficient of y will be +4, and it will get cancelled by -4 of second eqn, if we add these two eqns.
so,
10x + 4y = 20
3x - 4y = -46
---------------------
13x = -26 <--------------- by adding the two eqns, (+4y and -4y get cancelled)
---------------------
x = -26/13 = -2
For calculating y, put this value of x = -2 in any of the eqn,
5(-2) + 2y = 10
-10 + 2y = 10
2y = 10 + 10
y = 20/2 = 10
Did you get it now???
Now, can you solve the Question #3, (cows and chickens) the two eqns provided by me, by elimination method??? The graph already show you the answer.