WASHINGTON — The Republican-led House voted on Wednesday to delay core provisions of President Barack Obama's health care law, emboldened by the administration's concession that requiring companies to provide coverage for their workers next year may be too complicated. After a day of heated rhetoric, the House voted largely along party lines, 264-161, to delay by one year the so-called employer mandate of the Affordable Care Act. It voted 251-174 to extend a similar grace period to virtually all Americans who will be required to obtain coverage beginning Jan. 1, the linchpin of the law.