What is the solution of quadratic system of equations ?

(- 1, 1) and (- 5, - 35)

Step-by-step explanation:

since both equations express y in terms of x, equate the right sides

x² + 15x + 15 = - x² + 3x + 5 ( subtract - x² + 3x + 5 from both sides )

2x² + 12x + 10 = 0  ( divide all terms by 2 )

x² + 6x + 5 = 0 ← in standard form

(x + 1)(x + 5) = 0 ← in factored form

equate each factor to zero and solve for x

x + 1 = 0 ⇒ x = - 1

x + 5 = 0 ⇒ x = - 5

substitute these values into either of the 2 equations and solve for y

x = - 1 : y = (- 1)² + 15(- 1) + 15 = 1 - 15 + 15 = 1 ⇒ (- 1, 1 )

x = - 5 : y = (- 5)² + 15(- 5) + 15 = 25 - 75 + 15 = - 35 ⇒ (- 5, - 35 )

None of the given options

y = -⅔x + ²²/₃  

Step-by-step explanation:

1. Calculate the slope of EF

Assume E is at (-2, 5) and F is at (1, 3).

m₁ = (y₂ - y₁)/(x₂ - x₁) = (3 - 5)/(1 -(-2)) = -⅔

2. Calculate the slope of the parallel line

m₂ = m₁ = -⅔

3. Calculate its y-intercept

y = mx + b

6 =-⅔(2) + b

Simplify

6 = -⁴/₃ + b

Add ⁴/₃ to each side

b = 6 + ⁴/₃ = ¹⁸/₃ + ⁴/₃ = ²²/₃

The y-intercept is at (0,²²/₃).

4. Write the equation for the line

y = -⅔x + ²²/₃

The diagram shows EF in red. The parallel line in black passes through (2, 6) with a y-intercept at (0,²²/₃).