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Select the appropriate values of x that are solutions to f (x)=0, where f (x) = -7x^2 +4x+9

User Hanseh
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-7x^2 +4x+9=0\\ \Delta=4^2-4\cdot(-7)\cdot9=16+252=268\\ √(\Delta)=√(268)=2√(67)\\ x_1=(-4-2√(67))/(2\cdot(-7))=(-4-2√(67))/(-14)=(2+√(67))/(7)\approx1.46\\ x_2=(-4+2√(67))/(2\cdot(-7))=(-4+2√(67))/(-14)=(2-√(67))/(7)\approx-0.88\\