Question

What is the value of this expression below when z=3
10z^2-2z-2

Answer 1

82

Explanation:

Evaluate 10z² - 2z - 2 where z = 3:

`\longrightarrow` 10z² - 2z - 2 = 10 × 3² - 2 × 3 - 2

3² = 9:

`\longrightarrow` 10 × 9 - 2 × 3 - 2

10 × 9 = 90:

`\longrightarrow` 90 - 2 × 3 - 2

-2 × 3 = -6:

`\longrightarrow` 90 - 6 - 2

90 - 6 - 2 = 90 - (6 + 2):

`\longrightarrow` 90 - (6 + 2)

6 + 2 = 8:

`\longrightarrow` 90 - 8

`\longrightarrow` 82

Answer 2

82

Explanation:

10z^2-2z-2

10x3^2-2x3-2

90-6-2

90-8

82