Grade 8 - Review

Write a function rule for “The output is 5 greater than twice the input.”

• 5y= 2x

• y = 5 + 2x 

•      x = 5y + 2x

•    y = 5(2x)

1)    Find the value of x when y= 5 .

y = -3x + 8

• 13

• 8

• 1

• 5

Evaluate

• 30

• -25

• 32

• 9

Simplify the expression

• 81x

Write 823,566 as the product of a single digit and a power of 10.

• a)     8.23566 + 10⁴

• a)     82.8566 x 10⁴

• a)     8.23566 x 10⁵

• a)     823 x 10 x 10 x 10

Write 0.000000007214 as the product of a single digit and a power of 10

• 72. 14 x 10^-9

• 7.214 x 10^-9

• 7.214 x 10⁹

• 72.14 x 10⁹   

Find the approximate value of x and y

The cost C (in dollars) of producing x widgets in represented by C = 7.8x². How many widgets are produced if the cost is $3775.20?

• x = 61

• x = 780

• x= 484

• x = 22