Question 434776
Let x be the person's walking speed.
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4/x+3.5/(x+4.5)=6
Multiply each side by (x)(x+4.5)
4(x+4.5)+3.5(x)=6(x2+4.5x)
4x+18+3.5x=6x2+27x
8x+36+7x=12x2+54x
0=12x2+39x-36
0=(4x-3)(3x+12)
x=3/4,-4
His walking speed is .75 mph, jogging is 5.25
*[invoke quadratic "x", 12, 39, -36 ]