Answer:
The first integer is 56
The second integer is 84
The third integer is 49
Step-by-step explanation:
Define the variables
Let
x ----> the first integer
y ----> the second integer
z ----> the third integer
we know that
[tex]x+y+z=189[/tex] ----> equation A
[tex]x=y-28[/tex] ----> [tex]y=x+28[/tex] ----> equation B
[tex]y=(x+z)-21[/tex] ----> equation C
Equate equations B and C
[tex](x+z)-21=x+28[/tex]
subtract x both sides
[tex]z-21=28[/tex]
Adds 21 both sides
[tex]z=28+21[/tex]
[tex]z=49[/tex]
substitute the value of z in equation A
[tex]x+y+49=189[/tex]
[tex]x+y=189-49[/tex]
[tex]x+y=140[/tex] -----> equation D
Solve the system of equations B and D
[tex]y=x+28[/tex] ----> equation B
[tex]x+y=140[/tex] -----> equation D
substitute equation B in equation D and solve for x
[tex]x+x+28=140[/tex]
[tex]2x+28=140[/tex]
[tex]2x=140-28[/tex]
[tex]2x=112[/tex]
[tex]x=56[/tex]
Find the value of y
[tex]y=x+28[/tex] -----> [tex]y=56+28=84[/tex]
therefore
The first integer is 56
The second integer is 84
The third integer is 49