Mathematics
avtrisal
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-x2-3x+28 Factoring trinomals ax2+bx+c HELP. SHOW ALL WORK

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alexas89

[latex]-x^2-3x+28[/latex] To factoring this first we have to find the roots. [latex]-x^2-3x+28=0[/latex] [latex]x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}[/latex] [latex]x=\frac{-(-3)\pm\sqrt{(-3)^2-4*(-1)*28}}{2*(-1)}[/latex] [latex]x=\frac{3\pm\sqrt{121}}{-2}[/latex] [latex]x=\frac{3\pm11}{-2}[/latex] [latex]\boxed{\boxed{x_1=-7~~and~~x_2=4}}[/latex] Now we have to use this factoring [latex]a*(x-x_1)*(x-x_2)[/latex] therefore [latex](-1)*(x-(-7))*(x-4)[/latex] [latex]-(x+7)*(x-4)[/latex] [latex]\boxed{\boxed{-x^2-3x+28=(x+7)*(-x+4)}}[/latex]

Polieke

[latex]-x^2-3x+28=-(x^2+3x-28)=-(x^2+7x-4x-28)=\\\\=-[x(x+7)-4(x+7)]=-(x+7)(x-4)[/latex]

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