Slope is rise over run, i.e., y over x. So, to find slope, take your y values and subtract them. It doesn't matter which one first, just make sure whatever you decide matches with the way you subtract your x values. So, for this, I'll do 3 - -7. Subtracting a negative makes a positive, so you have 10. Do the same to your x values. -1 - 4 is -5. Now, you have the fraction 10/-5, which simplifies to -2. Your slope, therefore, is -2. Hope this helps!
Answer: 31
How: If there are two negative signs like this, you would connect them together and make it into a addition sign where you then can add them.
y = 3 x equation represents a proportional relationship.
Answer: Option B
<u>Step-by-step explanation:</u>
A proportional variation represents a relationship between two variables x and y. It can be expressed in the form y=k x. Here, the ‘k’, the proportionality constant is equal to the slope m and the line goes through the origin
case A) 
A linear equation that not passes through the origin and so not proportional variation
case B) y= 3 x
Is a linear equation but passes through the origin and so proportional variation
case C) y = - 3x+2
A linear equation that not passes through the origin and so not proportional variation
case D) 
An inverse variation equation but not passes through the origin and so not proportional variation.
From these, equation option B is the proportion equation because in these equations, there is no addition and subtraction of any constant number. That’s why both these equations become proportional equations.
A = amount invested at 4%.
b = amount invested at 9%.
we know the total amount invested was $26500, thus
a + b = 26500.
whatever% of anything is just (whatever/100) * anything.
how much is 4% of a? well, is just (4/100) * a, or
0.04a.
how much is 9% of b? well, is just (9/100) * b, or
0.09b.
we know the interest yielded for both amounts adds up to $1510, thus
0.04a + 0.09b = 1510.

how much was invested at 9%? well, b = 26500 - a.