Question 392680
(1) {{{2s - 13t = 120}}}
(2) {{{-14s - 91t = -840}}}
First, multiply both sides of (2) by {{{-1}}} to get:
(2) {{{14s + 91t = 840}}}
I notice that {{{7}}} divides each term, so, dividing each term,
(2) {{{2s + 13t = 120}}}
This is the same as (1) except for the sign of {{{13t}}} , so I'll
add (1) and (2)
(1) {{{2s - 13t = 120}}}
(2) {{{2s + 13t = 120}}}
{{{4s = 240}}}
{{{s = 60}}}
Now I plug this back into (1)
(1) {{{2*60 - 13t = 120}}}
(1) {{{120 - 13t = 120}}}
Subtract {{{120}}} from both sides
{{{-13t = 0}}}
{{{t = 0}}}
the solution is {{{s = 60}}},{{{t = 0}}}