1 )
1st and 2nd equation (multiply 1st by -2 ):
-2x - 10 y + 8 z = 20
2 x - y + 5 z = -9
---------------------------
- 11 y + 13 z = 11 / * ( -20 )
1st and 3rd:
- 2 x - 10 y + 8 z = 20
2 x - 10 y - 5 z = 0
-----------------------------
- 20 x + 3 z = 20 / * 11
----------------------------------
220 y - 260 z = -220
- 220 y + 33 z = 220
------------------------------
z = 0, y = -1, x = - 5
2 )
2 x - y + 5 = -4
- 2 x + 3 y - 5 = - 10
Substitution: y = 2 x + 9
- 2 x + 3(2 x + 9 ) = -5
4 x = - 32, x = -8, y = -7, z = 5
3 )
x + y + z = 11
1.5 x+3 y +1.5 z = 21
x = 2 y
------------------------
3 y + z = 11 / * (-2)
6 y + 1.5 z = 21
------------------------
- 6 y - 2 z = -22
6 y + 1.5 z = 21
------------------------
-0.5 z = -1, z = 2, y = 3, z = 6
Answer: the store used 6 pounds of peanuts, 3 pounds of almonds and 2 pounds of raisins.
Answer:
a) it has one real solution
Answer:
C
Step-by-step explanation:
5+2y+3z=5+3z+2yA
Intercambie los lados para que todos los términos de las variables estén en el lado izquierdo.
5+3z+2yA=5+2y+3z
Resta 5 en los dos lados.
3z+2yA=5+2y+3z−5
Resta 5 de 5 para obtener 0.
3z+2yA=2y+3z
Resta 3z en los dos lados.
2yA=2y+3z−3z
Combina 3z y −3z para obtener 0.
2yA=2y
Anula 2 en ambos lados.
yA=y
Divide los dos lados por y.
y
yA
=
y
y
Al dividir por y, se deshace la multiplicación por y.
A=
y
y
Divide y por y.
A=1
Step-by-step explanation:
cos 45° = distance to east / total distance=7,2
distance to east = cos 45° * 7,2 = 5,1 km
<h3>Question:</h3>
<em>Jon is selling tickets for the school talent show. On the 1st day, he sold 3 senior tickets and 12 child tickets for $195. On the 2nd day he sold 13 senior tickets for $299. Find the price of a senior citizen ticket.</em>
<h3>Answer:</h3>
Create a system of equations to help you solve this problem. The system of equations will look like: 3s + 12c = 195 and 13s = 299. The variable s represents the cost of senior tickets and the variable c represents the cost of children tickets.

Solve the second equation for the variable s as this is the easiest way to solve the problem. Solve the second equation for s by dividing both sides of the equation by 13 to isolate the variable s.
s = 23
Since the question was only asking for the price of a senior citizen ticket, you are technically done. The first equation was only put there to confuse you or allow you to check your work if you needed to. The price of a senior citizen ticket (variable s) is $23.