4. Find the value of the real number y such that (3+2i)(1 + iy)
is :
(a) real
(b) imaginary

Step-by-step explanation:

(3 + 2i)(1 + iy)

= 3 + (3y + 2)i - 2y (because i² = -1)

For this to be real, (3y + 2) = 0. => y = -2/3

For this to be imaginary, y can be any real or complex number (except -2/3)

518,400

step-by-step explanation:

the area is multiplying all the given measurements together.

40 * 18 * 30 * 24 = 518,400

answer:   expression= p+p*d%

price reduction + sale price = $625

sale price: $p+$p*d%

where d% is the percentage of discount

step-by-step explanation:

original price = p

price went down by $150 price reduction $p*d%

sale price= $ 475

therefore the price before sale is: $625

and the expression that shows the price before sale is: p+p*d%