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What are the zeros of the quadratic function f(x) = 2×2 + 16x – 9? x = –4 – and x = –4 + x = –4 – and x = –4 + x = –4 – and x = –4 + x = –4 – and x = –4 +

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 text {zeros of function:}  f (x) = 0 \\ f (x) = 2x ^ 2 + 16x-9  to2x ^ 2 + 16x-9 = 0     |  +9 \\ 2x ^ 2 + 16x = 9    |: 2 \\ x ^ 2 + 8x = 4.5 \\ x ^ 2 + 2x  cdot4 = 4.5    |  + 4 ^ 2  underbrace \\ {x ^ 2 + 2x  cdot4 + 4 ^ 2} _ {(a + b) ^ 2 = a ^ 2 + 2ab + b ^ 2} = 4.5 + 4 ^ 2  \ (x +4) ^ 2 = 20.5  iff x + 4 =  pm  sqrt {20.5}     |  -4 \\ x = -  sqrt {20.5} -4   vee  x =  sqrt {20.5} -4