Question

how the limits are changed​

Answer 1

Hmmm.......... I too don't know how

Answer 2

Step-by-step explanation:

$\tt The\: substitution \: is \: x + 1 = {t}^{2} \\ \\ \tt The\:initial\:limits\:where\:from\:8\:to\:15\\ \\ \tt When\:we\: substitute\:the\:limits\:changes \\ \\ \tt If\: x = 8 \: then 8 + 1 = {t}^{2} \\ \\ \tt So\: t = 3 \: This \: is \: the \: lower \: limit \\ \\ \tt similaraly \: for \: x = 15 \: then 15 + 1 = {t}^{2} \\ \\ \tt So\:t=4\: This\:is\:the\:upper\:limit\\ \\ \tt So\:the\:new\:limits\:are\:from\:3\:to\:4$