The answer is 57
729-669=
57
The solution to a system of (linear) equations is the point where the graphs intersect. Consider two parallel lines. By definition, two parallel lines never intersect each other, but all pairs of non-parallel lines will eventually intersect. That means they will also have a solution.
Let's consider what makes a line parallel to another line. It basically looks identical, having the same steepness (slope), but the graph is just shifted over. That is, a parallel line would have the same slope and a different y-intercept. For our equation

, or

in slope-intercept form, a parallel line will be of the form

.
That describes the form of a parallel line, which we do not want. Any other line, however, will give a solution to our system, so we merely want a line where the slope does not equal 2.
We can have any equation of the form

.
Answer:
X+2Y=7 and 4X+8Y=19
Step-by-step explanation:
Step 1: Write the equations in the form y=mx+c, where m represents the gradient.
In this case, gradient is equal to -0.5
Step 2: Now fix arbitrary values on the equation, y=mx+c while maintaining the value of m as - 0.5
You can make endless equations
Let the daily played number of pop songs be P, the number of rock songs be R and the number of hip-hop songs be H.
i)
"A radio station plays a total of 272 pop, rock, and hip-hop songs during a day"
means that : P+R+H=272
ii)
"The number of pop songs is 3 times the number of rock songs. "
so, P=3R
iii)
"The number of hip-hop songs is 32 more than the number of rock songs."
means: H=32+R
iv)
since both P and H can be written in terms of R, we have:
P+R+H=272
(3R)+R+(32+R)=272
3R+R+32+R=272
5R+32=272
5R=272-32=240
R=240/5=48
vi)
thus: P=3R=3*48=144, H=32+R= 32+48=80
Answer:
48 Rock, 144 Pop and 80 Hip-hop