In reply to @icecolbeveridge
@icecolbeveridge huh? It's just a sign error: -10T=-17.5T etc. means distance travelled is in the same direction as initial velocity. Should be -10T=17.5T...
In reply to @christianp
@icecolbeveridge and the acceleration is in the same direction as the distance travelled, so should be negative. Who sold you this formula? Get a refund!