Burger Joint is celebrating their grand opening. For 2 milkshakes and 3 burgers, the cost is $13. For 5 milkshakes and 7 burgers, the cost is $31. What is the cost of 1 burger plus one milkshake?
A $6.00
B) $5.50
C) $5.00
D) $4.50

answer: y=4000x+14000

step-by-step explanation:

hope this !

391.6 is the correct answer

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