Ch. 7 First Quiz Flashcards
How to tell if something is direct or inverse
Solve for y
Direct is multiplication
Inverse is division
y= kx
Direct
Y= k/x
Inverse
Joint Variation
Direct but with 2 or more things
Remember to check work
Check work
How to tell if a table is direct or inverse
Either plug the table into k=y/x for direct or plug the table into k=xy for inverse
If they all equal the same thing, they are direct/inverse
k= y/x
Direct
k=xy
Inverse
How to multiply
Get each equation into its simplest form and cancel anything
Write an answer and solve each thing canceled for zero, then write x cannot equal that number
How to divide
Keep, change, flip
Complete like a multiplication problem
How to write an equation with x and y that varies inversely
Plug given x and y into k=xy and solve
Write the y=k/x equation with the new x
Solve for y
How to write an equation with x and y that varies directly
Plug x and y into k=x/y and solve
Write the y=kx equation with the new x
Solve for y
How to subtract
Get a common denominator by simplifying as much as possible
Subtract the top by distributing the negative and keep the bottom the same
Simplify
No x cannot equal
How to add
Get a common denominator by simplifying as much as possible/multiplying the top and bottom
Add the top together and keep the bottom the same
Simplify
No x cannot equal
How to solve an equation with an equal sign using the LCD
Find the LCD
Multiply each term by what the denominator needs to be the LCD
Cancel the denominators out
Solve for x
If the equation is #*y= x, how to solve for y
y=x/#
Direct
How to add three terms
Multiply the top of each by the two denominators that they don’t have
Solve each one by doing parentheses first and then distributing
Simplify as much as possible and keep the denominator the same
How to rewrite an equation in k form
Choose a number you can take out of the x and that number to equal the denominator
Pick a number that will equal the original number when you subtract it before you take the number in front of the x out
Cancel the x+/- # and add the number in front of the x to the problem
The number after the x stays on top
The denominator is the same as the original denom.
How to solve word problems
Write 4 labels
1: Total cost
2: Original Group; x
3: New Group/ x+# or x-#
4: Difference
Write equation
Total/x - Total/x+/- # = difference
***If the equation difference gets larger the equation will be Total/x+/-# - Total/x = difference
