Raj tested his new flashlight by shining it on his bedroom wall. The beam of light can be described by the equation . How many inches wide is the beam of light on the wall?

12 inches

Step-by-step explanation:

Raj tested his new flashlight by shinning it on his bedroom wall the beam of the light can be described by the equation (x^2-2x) + (y^2-4y) - 31=0. how many inches wide is the beam of light on the wall

Solution

Given:

(x^2-2x) + (y^2-4y) - 31=0

By completing the square

(x^2-2x) + (y^2-4y) - 31=0

(x^2-2x+1-1) + (y^2-4y+4-4)-31=0

(x-1)^2 -1 + (y-2)^2 - 4 - 31=0

(x-1)^2 + (y-2)^2 - 1 - 4 - 31=0

(x-1)^2 + (y-2)^2 - 36=0

(x-1)^2 + (y-2)^2=36

Writing the equation in the form: (x-h)^2+(y-k)^2=r^2

(x-1)^2+(y-2)^2=6^2

From the above, r=6

Where,

r=radius

how wide is the diameter ?

radius=6

Diameter= 2 × radius

=2×6

=12 inches

rick has $1400 and sally has $1500

step-by-step explanation:

to find amount of money rick has after 10 years :

principal = $1000 , time = 10 years , rate = 4% annually

to find amount of money sally has after 10 years :

her friend gives to pay her $50 per year, therefore money she has after 10 years = 50 × 10 = $500

also, sally gets $1000 after 10 years,

therefore, total amount of money sally has after 10 years = 500 + 1000 = $1500

so, after 10 years : rick has $1400 and sally has $1500