Answer:
1) Distance=Speed*time
90=(x+1)*(x)+(2x+5)(x-1)
90=x^2+x+2x^2-2x+5x-5
3x^2+4x-95=0
2) 3x^2+4x-95=0. Using quadratic formula, we get
x=(-4±sqrt(16-4*3*(-95)<u>)</u>)/6, x=5 or - 19/5 but since x also represents time, it can't be negative.
3) Total time take she took for the journey is x+x-1=2x-1=2*5-1=9 hours
The equation of a line is mx+b
Both expression have the same denominator: 9x²-1. Thus it must not be 0.
9x²-1=(3x-1)(3x+1)=0, resulting x=+-1/3.
Restrictions: x in R\{-1/3, 1/3}
Adding those expressions:
E=(-x-2)/(9x²-1 ) + (-5x+4)/(9x²-1)=
(-x-2-5x+4)/(9x²-1)=(-6x+2)/(9x²-1)=
(-2)(3x-1)/(9x²-1)=-2/(3x+1)
E=-2/(3x+1)
Ben - 8 years old
Ishaan - 2 years old
