Find two numbers whose sum is 26 and whose product is 165.

Let the two numbers be a and b and use the sum and product to write two equations with two unknowns
a + b = 26 and a b = 165
Solve the first equation for b
b = 26 - a
Substitute b in the equation a b = 165 by 26 - a
a (26 - a) = 165
Write the above equation in standard form
- a 2 + 26 a - 165 = 0
Solve the above equation for a
a = 11 and a = 15.
Use b = 26 - a to find b
when a = 11 , b = 15 and when a = 15 , b = 11.
The two numbers are 11 and 15.
correct answer C