Какое из следующих уравнений является линейным?<img src="/close/store/examRes/%7B6F778F18-CC53-4FBA-BCCA-8DC3ABA85B19%7D/12.gif" /><img src="/close/store/examRes/%7B6F778F18-CC53-4FBA-BCCA-8DC3ABA85B19%7D/10.gif" /><img src="/close/store/examRes/%7B6F778F18-CC53-4FBA-BCCA-8DC3ABA85B19%7D/13.gif" /><img src="/close/store/examRes/%7B6F778F18-CC53-4FBA-BCCA-8DC3ABA85B19%7D/9.gif" /> <img src="/close/store/examRes/%7B6F778F18-CC53-4FBA-BCCA-8DC3ABA85B19%7D/10.gif" />, <img src="/close/store/examRes/%7B6F778F18-CC53-4FBA-BCCA-8DC3ABA85B19%7D/12.gif" />, <img src="/close/store/examRes/%7B6F778F18-CC53-4FBA-BCCA-8DC3ABA85B19%7D/13.gif" />, <img src="/close/store/examRes/%7B6F778F18-CC53-4FBA-BCCA-8DC3ABA85B19%7D/9.gif" />