Maggie's brother is 3 years younger than three times her age. The sum of their ages is 21.
How old is Maggie?
Maggie is
years old

Maggie is 6 years old.

Maggie's brother is 15 years old

Step-by-step explanation:

Take Maggie's age as 'x'

Her brother's age = 3x - 3

Sum of their ages = 21

Hence,

Maggie's age + brother's age = 21

(x) + ( 3x-3 ) = 21

x + 3x - 3 = 21

4x = 21 + 3

4x = 24

x =

x=  6

Maggie's age = x = 6

Her brother's age = 3x - 3

                              = 3(6) -3

                              = 18 - 3

                               = 15 years

Hope this helps.

step-by-step explanation:

y = 3x+4

step-by-step explanation:

to find the slope

slope = (y2-y1)/ (x2-x1)

    = (-8-4)/ (-4-0)

    = -12/-4

  = 3

using the slope intercept form of a line

y= mx+b

we know the slope is 3

we know the y intercept is 4 ( the point where it crosses the y axis or x=0)

y = 3x+4