Find the coordinates of the intersection points of the parabola y = x square -14 and the line x + y = 6
August 7, 2021 | education
| At the points of intersection of the graphs, the x and y coordinates of both functions are equal.
y = x² – 14; x + y = 6.
Express y from the second equation and substitute it into the first equation:
x + y = 6; y = 6 – x.
x² – 14 = 6 – x;
x² – 14 – 6 + x = 0;
x² + x – 20 = 0
We solve the quadratic equation using the discriminant:
a = 1; b = 1; c = -20;
D = b² – 4ac; D = 1² – 4 * 1 * (-20) = 1 + 80 = 81 (√D = 9);
x = (-b ± √D) / 2a;
x1 = (-1 – 9) / 2 = -10/2 = -5.
x2 = (-1 + 9) / 2 = 8/2 = 4.
Let’s calculate the value of y: y = 6 – x.
x = -5; y = 6 – 5 = 1. Point (-5; 1).
x = 4; y = 6 – 4 = 2. Point (4; 2).
Answer: The coordinates of the intersection points are (-5; 1) and (4; 2).
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