7 x 2 − 31 x + 20 = 0 First, remove the coefficient by division So 7 7 x 2 − 7 31 x + 7 20 = 0 Then, cancel out 7 20 So, x 2 − 7 31 x + 7 20 − 7 20 = − 7 20 Then take half of the coefficient, then square it. 2 − 7 31 = 14 37 ( − 14 37 ) 2 = 196 961 So, The equation already looks like this: x 2 − 7 31 + 196 961 = − 7 20 + 196 961 So, x 2 − 7 31 + 196 961 = 196 401 Then factor the left side of the equation: ( x − 14 31 ) 2 = 196 401 Then square both sides: x − 14 31 = 196 401
7 x 2 − 31 x + 20 = 0 Δ = ( − 31 ) 2 − 4.7.20 = 961 − 560 = 401 x = 2 ∗ 7 31 \pmsqrt 401 = 14 31 ± 401
To factor the quadratic equation 7 x 2 − 31 x + 20 = 0 , we first find two numbers that replace the middle term, ultimately leading us to factor it as ( 7 x − 5 ) ( x − 4 ) = 0 . The solutions to the equation are x = 7 5 and x = 4 .
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