Answer:
r=8
Step-by-step explanation:
The formula for slope is
m = (y2-y1)/ (x2-x1)
Substitute in what we know.
8/3 = (-7-1)/(5-r)
Simplify
8/3 = -8/(5-r)
We can use cross products to help us solve.
8 * (5-r) = 3 * (-8)
divide each side by 8
8/8 * (5-r) = 3 * (-8)/8
5-r = -3
Subtract 5 from each side
5-r-5 = -3-5
-r = -8
Multiply by -1
r = 8
In order to isolate any term from an equation we need to clear out any different variable or numbers different from the one we want
in this case I is being multiplied by R, so we need to do the opposite which is divide in order to eliminate
But since this is an equality we must do it on both sides so de equation does not get altered
Then we simplify the equation
The product of something means multiplying the terms together.
(2x+3) (4x^2-5x+6)
Secondly you need to distribute the terms to each other (Think of problems like FOIL)
2x * 4x^2 + 2x(-5x) + 2x * 6 + 3 * 4x^2 + 3(-5x) + 3 * 6
Then you must take into account that some of the numbers are negative. (minus-plus rules!)
2x * 4x^2 - 2x * 5x + 2x * 6 + 3 * 4x^2 - 3 * 5x + 3 * 6
Now is the tricky part of simplifying everything.
2x * 4x^2 = 8x^3
2x * 5x = 10x^2
2x * 6 = 12x
3 * 4x^2 = 12x^2
3 * 5x = 15x
3 * 6 = 18
8x^3 - 10x^2 + 12x + 12x^2 - 15x + 18
Then you group like terms.
8x^3 - 10x^2 + 12x^2 - 3x + 18
8x^2 + 2x^2 - 3x + 18
The trickiest part of this is distributing all of the terms within the parentheses, once you've done that, it's smooth sailing!
