Answer:
C) {6+√43, 6-√43}
Step-by-step explanation:
Applying,
x = [-b±√(b²-4ac)]/2a.................... Equation 1
From the question,
Given: a = 1, b = -12, c = 7
Substitute these values into equation 1
x = [-(-12)±√(-12²+4×1×7)]/2×1
x = [12±√(144+28)]/2
x = [12±√172]/2
either,
x = (12-√172)/2
x = (12-2√43)2
x = (6+√43)
or
x = (12+√172)/2
x = (12+2√43)/2
x = (6+√43)
Hence,
The right answer is C). {6+√43, 6-√43}
