What multiplies to get 400 but adds to get 120?

Answer 1

520

Answer 2

To find two numbers that multiply to get 400 but add to get 120, we can set up a system of equations. Let's call the two numbers x and y. We know that xy = 400 and x + y = 120. By substituting y = 120 - x into the first equation, we get x(120 - x) = 400. Simplifying this equation gives us x^2 - 120x + 400 = 0. Solving this quadratic equation will give us the two numbers that satisfy the conditions.

Answer 3

116.5685 and 3.4315 (accurate to 4 decimal places)

1. x * y = 400

2. x + y = 120

Rearranging 2 gives

3. y = -x + 120

Substituting this value for y into 1. gives

x * (-x + 120) = 400

-x2 + 120x = 400

-x2 + 120x - 400 = 0

This is now a quadratic equation and can be solved using the quadratic formula.

x = (-120 +/- (1202 - 4*-1*-400)1/2) / (2 * -1)

x = 116.5685 and 3.4315 (to 4 decimal places)