T+8-8t=(1-t)(1+t))×2

Question

T+8-8t=(1-t)(1+t))×2

Answer 1

T+8-8t=1+t-t-t^2×2
t+8-8t-1-2t^2=0
2t^2+7t-7=0 (сократим на 2)
t^2+3,5t-3,5=0
t1+t2=-3,5
t1×t2=-3,5