Two numbers have a product of 20. The second number is three less than twice the first number. What are the two numbers? 1
2
3
4
5
6
7
8
9
10

4 and 5

Step-by-step explanation:

xy = 20

x = 2y - 3

(2y-3)y = 20

2y^2 - 3y = 20

2y^2 - 3y - 20 = 0

Solve the quadratic equation

you get y = 4, -5/2

Use 5 since it is one of the options

xy = 20, y = 4

x = 5

both equations and proportions are better.

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15