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\begin{array}{ll}x-\frac{2}{5}=0 \text { or } x-\frac{3}{4}=0 & \text { Set each factor equal to } 0 . \\5 x-2=0 \text { or } 4 x-3=0 & \text { Multiply both sides of the equation to eliminate fractions. } \\f(x)=(5 x-2)(4 x-3) & \text { Create the quadratic function, multiplying the factors. } \\f(x)=20 x^{2}-23 x+6 & \text { Expand the polynomial. } \\f(x)=(5 \cdot 4) x^{2}-23 x+(2 \cdot 3) &\end{array}