If a graph is proportional then the line will go through the origin at point (0, 0). If the equation is proportional then it will be in the form of y=kx with no other operations after. The constant of proportionality is another way to say the slope and in your specific equation the slope would be 1/5.
-x - y = 8
2x - y = -1
Ok, we are going to solve this in 2 parts. First we have to solve for one of the variables in one of the equation in terms of the other variable. I like to take the easiest equation first and try to avoid fractions, so let's use the first equation and solve for x.
-x - y = 8 add y to each side
-x = 8 + y divide by -1
x = -8 - y
So now we have a value for x in terms of y that we can use to substitute into the other equation. In the other equation we are going to put -8 - y in place of the x.
2x - y = -1
2(-8 - y) - y = -1 multiply the 2 through the parentheses
-16 - 2y - y = -1 combine like terms
-16 - 3y = -1 add 16 to both sides
-3y = 15 divide each side by -3
y = -5
Now we have a value for y. We need to plug it into either of the original equations then solve for x. I usually choose the most simple equation.
-x - y = 8
-x - (-5) = 8 multiply -1 through the parentheses
-x + 5 = 8 subtract 5 from each side
-x = 3 divide each side by -1
x = -3
So our solution set is
(-3, -5)
That is the point on the grid where the 2 equations are equal, so that is the place where they intersect.
Answer:
Let x = the third side
In a triangle, the sum of any 2 sides must be larger than the third side.
I believe this is called the triangle inequality theorem.
We can construct 3 inequalities to obtain the range of values for the third side.
(Inequality #1) 12 + 4 > x
16 > x
(Inequality#2) 12 + x > 4
x > -8 (we can discard this ... we know all sides will be positive)
(Inequality #3) 4 + x > 12
x > 8
So when we combine these together,
8 < x < 16
X (the third side) must be a number between 8 and 16. but not including 8 and 16
Answer:
x = -2.585
Step-by-step explanation:
You will have to plug this into your graphing calculator.
In y=, type 5(1/2)^x in the Y1 and type 30 in Y2.
When you hit 2nd trace and hit find intersections, you will get (-2.585, 30).
The answer is x = -2.585
