Solve the second equation for y so that you can substitute it in for y in the first equation..
y = 5x - 4
Substitute:
3x + (5x - 4) = 1
Answer:

Step-by-step explanation:
Given: 
Since the equation is written in slope-intercept form, it is extremely easy to find the y-intercept. Slope-intercept form is written as:

Whereas:
y: range
m: slope
x: domain
b: y-intercept
With that in mind, we can immediately tell that 6 is the y-intercept.
Answer:
The value of 0 is 0 - If you want to round its 37.1
Step-by-step explanation:
The value of 0=0
0
any other # besides zero
if you are wanting to round, you can round to the tenths place and say that 37.06 rounds up to 37.1
The percentages increased by 13% in 2007
So x=x
and y=pounds
when x=0, y=64
when x=1, y=63.1
to find slope, (y1-y2)/(x1-x2)=(64-63.1)/(0-1)=0.9/-1=-0.9=slope
y=-0.9x+b
subsitute
64=-0.9(0)+b
b=64
y=-0.9+64
so int 2001, x=11
y=-0.9(11)+64
y=-9.9+64
y=54.1