Answer:

Step-by-step explanation:





Step-by-step explanation:
x = father's age now
y = son's age now
x = 2y + 10
x - 20 = 5(y - 20) = 5y - 100
using the first in the second equation :
2y + 10 - 20 = 5y - 100
-10 = 3y - 100
90 = 3y
y = 30
x = 2y + 10 = 2×30 + 10 = 60 + 10 = 70
the father is now 70 years old, the son now 30 years old.
The answer to 89+27+11 is 127
Let n = length
let n-4 = width since it is 4 meters shorter
2( n+n-4) =72 Two of the length and width added together equal the perimeter
combine like terms
2(2n -4) = 72 Now use the distributive law on the left side of the equation
4n -8 = 72 Now add 8 to both sides
4n -8 +8 = 72 +8
4n = 80 Finally divide each side by 4
n=20
so the length is 20 and the width is 4 less or 16.
Let's see if our answer works.
20 + 16 + 20 +16 =? 72
72 =72 yes, it does. Length = 20 Width = 16