Justin's 8th Grade Math Review!

combine like terms

100

5+9t+3

9t+8

200

y+2+2y+7

3y+9

300

9t² - 3t -5t + 6 

9t² - 8t + 6

400

z+z+4b-3z+5b+8-9

-z + 9b - 1

500

-x + 7 +6x² -5x + 7x² -8 

13x² - 6x -1

using distributive property

100

3(x-3)=12

x=7

200

-5(x+9)=-5

x= -8

300

8(x-2)+11=35

x=5

400

2x - 3(2x-3) + 4 = 33

x= -5

500

3(2x+2) -4(x-5) = 18

x = -4

solving linear equations with substitution

100

- 7x - 6y = 4

x= - 3y + 8

x= -4

y= 4

200

-3x + 3y =3

-5x + y = 13

(-3,-2)

300

x + 3y = 6

2x + 8y = -12

(42,-12)

400

(1/3)x + y = 6

(1/2)x - (1/4) = 2

(6,4)

500

-3x +3y = 4

-x + y+3

no solution

solving systems with setting equations equal

100

y= 2x -11

y = 3x -14

(3, -5)

200

x = 3y + 4

x = 2y -2 

(-14,-6)

300

y=4(x-3)

y=8(x+7)

(-17,-80)

400

The perimeter and area of a rectangular cake are equal.

Perimeter= 3x+4

Area = 12x - 2

What is the value of the area and perimeter in inches?

(x=2/3)

Perimeter=6 in

Area=6 in

500

y = 5(x+2) - 9

3x + y = 2

x = 1/8

y = 15/24 or y=5/8

solving equations with variables on both sides

100

5x - 2 = 3x + 4

x=3

200

15 + 6x = 45 + 8x

x= -15

300

2(10-2x) = 4(2x+2)

x=1

400

-7x - 3x + 2 = - 8x -8

x=5

500

-6n -20 = -2n +4(1-3n)

n=3