Final answer:
Reagan and conservative Republicans believed that tax cuts would help all Americans by stimulating economic growth, increasing potential output, and creating more job opportunities.
Step-by-step explanation:
President Reagan and his economic advisors believed that tax cuts would help all Americans because they subscribed to the theory of supply-side economics. The theory behind this is that by reducing taxes on the wealthy, they would have more money available to invest in their businesses, which would create jobs and stimulate economic growth
Thus, they argued that high taxes were discouraging people from working harder and investing more in businesses. By reducing taxes, Reagan and conservative Republicans believed that it would stimulate economic growth, increase potential output, and create more job opportunities for all Americans.