Expand and combine like terms.
(x+3)(x+4)

x^2  +7x+12

Step-by-step explanation:

(x+3)(x+4)

FOIL

first x*x= x^2

outer: 4x

inner:3x

Last 3*4=12

Add together

x^2+3x+4x+12

Combine like terms

x^2  +7x+12

5y

step-by-step explanation:

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.