Susan is 5 years older than her sister. The sum of their ages are 51. Define a variable. Then write an equation that could be used to find their ages

We will say the variable to be x.

So we will say her sister is x years old.

susan is x + 5 years old

susan = x+5

sister = x

the equation wll be (x + 5) + x = 51

ans = (x+5) + x = 51

if you want to continue

yo first collect the like terms wich are the variables that look alike and simplify them

in this case you take x and add to x making it 2x

then you cross 5 to the other side of the equal sign

then because t is positive it will turn to negative. then you will minus it wiy=th 51

in equation form it is done like this;

(x+5) + x = 51

x+x + 5 = 51

2x + 5 = 51

→

2x = 51 - 5

2x = 46

2x/2 = 46/2

x = 23

if her sister is 23 years old then susan is 23 + 5 years old

You would do

51-5 = 46

then you would divide

46/2 = 23

so Susan is

23+5=28

Susan is 28 years old and her sister is 23

28+23=51