Answer:

Step-by-step explanation:
The slope-intercept form is
, where m is the slope of the line and c is where the line crosses the
-axis.
To calculate
we can use the formula
where
is the difference in
between two points and
is the difference between
.
Information we can get from the graph given:
. Since
is the point at which the line crosses the
-axis.
To find
let's get two points from the graph.
Point 1: 
Point 2: 
Now use the equation
.
.
Now we have
and
, let's put them back into the general equation.

I don't know if this helps/if you have learned this yet but it is a characteristic of a parallelogram that opposite sides are congruent. If this does not help please respond and I will do my best to help! I don't know if I 100% understand what you are asking!
Answer:
Sydney's age is 28
Step-by-step explanation:
Let Devaughn be D
And Sydney be S
D=S+8..... equation 1
D+S=64...... equation 2
Substitute equation 1 to equation 2
S+8+S=64
2S+8=64
2S=64-8
2S=56
S=56/2
S=28
Hope it helps
Good luck