Question

If you were using the quadratic formula to solve the following equation and a = 2, what value would you use for the variable 'b'? 2x2 + 5x = 3x - 4

Answer 1

$\bf 2x^2+5x=3x-4\implies 2x^2+2x=-4\implies 2x^2+2x+4=0 \\\\[-0.35em] ~\dotfill\\\\ ~~~~~~~~~~~~\textit{quadratic formula} \\\\ \stackrel{\stackrel{a}{\downarrow }}{2}x^2\stackrel{\stackrel{b}{\downarrow }}{+2}x\stackrel{\stackrel{c}{\downarrow }}{+4}=0 \qquad \qquad x= \cfrac{ - b \pm \sqrt { b^2 -4 a c}}{2 a}$