Find the slope of the line through:
(-3,7) and (-3, 12)

hope this works

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets

Parenthesis

Exponents

Multiplication

Division

Addition

Subtraction

Left to Right

Algebra I

Coordinates (x, y)

Slope Formula:  

Step-by-step explanation:

Step 1: Define

Point (3, 7)

Point (6, 11)

Step 2: Find slope m

Simply plug in the 2 coordinates into the slope formula to find slope m

Substitute in points [Slope Formula]:                                                                

[Fraction] Subtract:                                                                                            

she invested x amount at 10%, so 0.10x

she then invested 30,000 - x qt 7%, so 0.7(3-x)

they both earned 2400:

0.10x + 0.07(3-x) = 2400

now solve for x:

0.10x + 2100 - 0.07x = 2400

combine like terms:

0.03x + 2100 = 2400

subtract 2100 from both sides:

0.03x = 300

divide both sides by 0.03:

x = 300 / 0.03

x = 10,000

she invested $10,000 at 10% and $20,000 at 7%