Determine the factor of a polynomial equation including piecewise functions

[euro94]

The height,h, in meters, of a weather balloon above the ground after t seconds can be modeled by the function h(t)=-2t^3 + 3t^2 +149t + 410 for 0< t < 10. When is the balloon exactly 980m above the ground?

980 = -2t³ + 3t² +149t + 410
0 = -2t³ + 3t² +149t - 570

 

[tiny-tim]

hi euro94!

in exam questions like this, it's almost always a whole number,

so try 1, 2, 3 ,4 ,5 ,… ​

 

[euro94]

Thanks :)
Can you please help me with this question :)

Maria designed a rectangular storage unit with dimensions 1m by 2m by 4m. By what shoulds he increase each dimension to produce an actual storage that is 9 times the volume of his scale model?

v= (1) (2) (4)
v= 8

v has to be 9 times larger
v= (x+1) (x+2) (x+4)

How do i find the value of x?

 

[tiny-tim]

erm …

same method? ​

(and I'm off to bed :zzz:)