Question 1154148
<br>
{{{a^2+3ad+2d^2 = (a+d)(a+2d) = 15}}}<br>
{{{2a+3d = (a+d)(a+2d) = 8}}}<br>
So (a+d) and (a+2d) are two numbers whose product is 15 and whose sum is 8.<br>
The two numbers are, in some order, 3 and 5.<br>
So either<br>
(a) {{{a+d=3}}} and {{{a+2d=5}}} --> d=2; a=1 -->  1, 3, 5, 7, ...<br>
OR<br>
(b) {{{a+d=5}}} and {{{a+2d=3}}} --> d=-2; a=7 -->  7, 5, 3, 1, ...<br>