Find the sum of the coordinates of the intersection points of the graphs of the functions y = 2x-4 and y = √ (x ^ 2 – x + 4).
July 22, 2021 | education
| To find a solution to the problem, we will compose and solve a system of these equations:
System of equations:
y = 2x – 4;
y = √ (x ^ 2 – x + 4).
We solve using the substitution method. Substitute the expression from the second into the first equation instead of y:
2x – 4 = √ (x ^ 2 – x + 4);
4x ^ 2 – 16x + 16 = x ^ 2 – x + 4;
3x ^ 2 – 15x + 12 = 0.
We calculate the discriminant of the equation:
D = 15 ^ 2 – 4 * 3 * 12 = 81.
x1 = (15 + 9) / 6 = 4;
x2 = (15 – 9) / 6 = 1.
y1 = 2 * 4 – 4 = 4;
y2 = 2 * 1 – 4 = -2.
(4; 1) and (4; -2).
We are looking for the sum of the coordinates of the points:
(8; -1).
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