What is the solution to the system of equations?
1 answer:
Answer:
(8 - 12 )
Step-by-step explanation:
Given
x -
y = 8
x +
y = - 5
Multiply both equations through by 4 to clear the fractions
x - 2y = 32 → (1)
2x + 3y = - 20 → (2)
Multiplying (1) by - 2 and adding to (2) will eliminate the x- term
- 2x + 4y = - 64 → (3)
Add (2) and (3) term by term to eliminate x
0 + 7y = - 84
7y = - 84 ( divide both sides by 7 )
y = - 12
Substitute y = - 12 into either of the 2 equations and solve for x
Substituting into (1)
x - 2(- 12) = 32
x + 24 = 32 ( subtract 24 from both sides )
x = 8
solution is (8, - 12 )
You might be interested in
Answer:
θ = (60° )
Step-by-step explanation:
Using the identity
sin²x + cos²x = 1 ⇒ sin²x = 1 - cos²x
Given
cos²θ - sin²θ = 2 - 5cosθ
cos²θ - (1 - cos²θ) = 2 - 5cosθ
cos²θ - 1 + cos²θ = 2 - 5cosθ
2cos²θ - 1 = 2 - 5cosθ ( subtract 2 - 5cosθ from both sides )
2cos²θ + 5cosθ - 3 = 0 ← in standard form
(cosθ + 3)(2cosθ - 1) = 0 ← in factored form
Equate each factor to zero and solve for θ
cosθ + 3 = 0
cosθ = - 3 ← not possible as - 1 ≤ cosθ ≤ 1
2cosθ - 1 = 0
cosθ = , so
θ = (
) =
( or 60° )