At the BOBA CLUB you must be a member to buy boba. A membership cost $4. Once you are a member of BOBA CLUB each Boba drink is $2. At JACK’S BOBA you do not need to be a member. Anyone can walk in JACK'S BOBA shop and buy one drink for $3 Boba Club: y=2x+4
Jacks Boba: y=3x

Which is cheaper if you want to buy 7 boba drinks? How much cheaper? What is the solution to the system of equation?

Boba Club is cheaper if you want to buy 7 Boba drinks. It's cheaper by 3.

Step-by-step explanation:

Boba Club: y=2x+4

Jack's Boba: y=3x

Replace the X variable with 7 for both equations. For Boba Club, multiply 2 by seven to get 14, then add four to get 18. For Jack's Boba, multiply 3 and 7 to get 21. Boba Club is cheaper. (What would you need 7 Boba drinks for though?)

x^2 + 81

we can factor this using difference of square binomials.

rewrite the equation:

x^2 - (-81)

factor:

(a^2 - b^2) = (√a^2 + √b^2)(√a^2 - √b^2)

(x^2 - (-81) = (x + √-81)(x - √-81)

we can remove the - from under the radical by multiplying it by i.

(x^2 - (-81) = (x + i√81)(x - i√81)

(x^2 - (-81) = (x + 9i)(x - 9i)

we can check our answer by using foil:

x^2 - 9ix + 9ix - 81i^2

x^2 - 81^2

i^2 = -1

x^2 + 81