Make the number x & y x*y=-240240 x+y=-8 < you can rearrange this as x=-8-y Now substitute in this rearrangement (-8-y)*y=-240 -8y-y² =-240 (add y² and 8y) 0=y²+8y-240 (now factorise the equation) 0=(y+20)(y-12) (for 2 things to multiply and equal zero one or both has to equal zero) so y+20=0 and/or y-12=0 so y=-20 or y=12 Now substitute these into x+y=-8 to get x y=-20 then x=12 y=12 then x=-20
08-Oct-2009 — If a spherical balloon has a volume of 972 pi cubic centimeters, what is ... is 4.pi.r^2 (its area remember not volume) as 4/3.pi.r^3=972pi r=9 ... and it is good to know the squares of the next 10 numbers.
