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Please help me. i have no idea what to do

Please help me. i have no idea what to do-example-1

1 Answer

1 vote

Answer:

F

Explanation:

(x + 2)² + (y - 3)² = 37

intersection points with the x-axis means that their y-values are 0 !

that is the whole trick, as I am sure you experienced already with lines and y-intersects (x = 0) and x-intersects (y =0).

so, we need to solve for x, when y = 0 :

(x + 2)² + (-3)² = 37

x² + 4x + 4 + 9 = 37

x² + 4x - 24 = 0

the solution to a quadratic equation

ax² + bx + c = 0

is

x = (-b ± sqrt(b² - 4ac))/(2a)

in our case

x = (-4 ± sqrt(4² - 4×1×-24))/(2×1) =

= (-4 ± sqrt(16 + 96))/2 = (-4 ± sqrt(112))/2 =

= (-4 ± sqrt(16×7))/2 = (-4 ± 4×sqrt(7))/2 =

= -2 ± 2×sqrt(7)

x1 = -2 + 2×sqrt(7)

x2 = -2 - 2×sqrt(7)

so, F is the right answer.

User Kochez
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