Question 1087273
Variance known, small sample size.
So then,

{{{t=((x[1]-x[2])-(mu[1]-mu[2]))/sqrt(sigma[1]^2/n[1]+sigma[2]^2/n[2]))}}}
{{{t=((80-135)-(0))/sqrt(550/10+100/14))}}}
{{{t=(-55)/sqrt(435/7))}}}
{{{t=(11/87)sqrt(3045)}}}