<span>6y-3(y-1)=4+5y </span>
<span>6у-3у+3=4+5у</span>
<span>3у-5у=4-3</span>
<span>-2у=1</span>
<span>у=-1/2=-0,5</span>
2250:100x15=337.5 скидка с одного комплекта