101k views
2 votes
Weekend: The product of the two numbers is 144 and their difference is 10. What is the sum of the two numbers?​

User Sevara
by
4.1k points

1 Answer

4 votes

Answer:

There are two pairs of numbers:

-8 -18

and

18 8

Explanation:

a * b = 144 EQ. 1

a - b = 10 EQ. 2

From EQ. 2:

a = 10 + b EQ. 3

Replacing EQ. 3 in EQ. 1:

(10+b)b = 144

10*b + b*b = 144

b² + 10b - 144 = 0

b = {-10±√((10²)-(4*1*-144))} / (2*1)

b = {-10±√(100+576)} / 2

b = {-10±√676} / 2

b = {-10±26} / 2

b₁ = {-10-26} / 2 = -36/2 = -18

b₂ = {-10+26} / 2 = 16/2 = 8

a₁ - b₁ = 10

a₁ - (-18) = 10

a₁ + 18 = 10

a₁ = 10 - 18

a₁ = -8

a₂ - b₂ = 10

a₂ - 8 = 10

a₂ = 10 + 8

a₂ = 18

Check:

a₁ * b₁ = -8 * -18 = 144

a₂ * b₂ = 8 * 18 = 144

User Junya Kono
by
3.5k points