Thomas is starting a new company. he has two quotes from a computer company for the cost of computers and printers. if he buys three computers and one printer, the cost is $825. if he buys 4 computers and 2 printers, the cost is $1200. how much does each computer and printer cost?

1,918

step-by-step explanation:

$119.20

step-by-step explanation:

$372.50 - 60% off is $149. $149-20% off is $119.20

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x

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