Answer:
Step-by-step explanation:
Notice that in the second equation, the coefficient of 
is 
times greater than in the first. Therefore, by making the coefficient of 
in the second equation times greater than in the first, it's impossible to only isolate one variable.
Therefore, when 
, there are no solutions to this system.
Hello
cos ( x + pi/2) =cos(x)cos(pi/2)-sin(x) sin(pi/2)
= cos(x)×0-sin(x) ×1
cos ( x + pi/2) = - sin(x)
Five less than a number n
Answer:
a = 3, b = -1, c = 10
Step-by-step explanation:
Let the three numbers be a, b and c.
Equation 1: a + b + c = 12
Equation 2: a + 2b + 3c = 31
Equation 3: 9b + c = 1
Equation 2 - Equation 1:
Equation 4: b + 2c = 19
Equation 3 times by the number 2
Equation 5: 18b + 2c = 2
Equation 5 - Equation 4
17b = -17
b = -1
Substitute into Equation 4:
2c - 1 = 19
2c = 20
c = 10
Substitute into Equation 1:
a + b + c = 12
a - 1 + 10 = 12
a = 3
