The revenue (in millions of dollars) from the sale of $x$ units at a home supplyoutlet is given by $R(x)=0.21 x$. The profit (in millions of dollars) from the sale of $x$ gunits is given by $P(x)=0.086 x-1.3$ (a) Find the cost equation. (b) What is the cost of producing 7 units? (c) What is the break-even point? (a) $C(x)=$ (Use integers or decimals for any numbers in the equation.) (b) The cost of producing 7 units is $\$ \square$ million. (Type an integer or a decimal.) (c) The break-even point occurs when about units are sold. (Round to the nearest thousandth as needed.)

Step 1 ：Given the revenue function \(R(x) = 0.21x\) and the profit function \(P(x) = 0.086x - 1.3\), we can find the cost function by subtracting the profit function from the revenue function. This gives us \(C(x) = R(x) - P(x)\).

Step 2 ：Substituting the given functions into the equation, we get \(C(x) = 0.21x - (0.086x - 1.3)\). Simplifying this equation gives us the cost function \(C(x) = 0.124x + 1.3\).

Step 3 ：To find the cost of producing 7 units, we substitute \(x = 7\) into the cost function. This gives us \(C(7) = 0.124*7 + 1.3 = 2.168\). So, the cost of producing 7 units is \$2.168$ million.

Step 4 ：The break-even point occurs when the profit is zero. So, we need to solve the equation \(P(x) = 0\) for \(x\). This gives us \(0.086x - 1.3 = 0\). Solving for \(x\) gives us \(x = 15.116\). So, the break-even point occurs when about 15.116 units are sold.

Step 5 ：Final Answer: \(\boxed{C(x) = 0.124x + 1.3}\), \(\boxed{\text{The cost of producing 7 units is } \$2.168 \text{ million}}\), \(\boxed{\text{The break-even point occurs when about 15.116 units are sold}}\)