Step-by-step explanation:

Formula of Area of a rectangle

Length x width = Area

Let

l = length

w = width

a = area

Given:

a = 9 - 30z + 25z²

SOLUTION:

25z² - 30z + 9 = 0

25z² - 30z + 9 - 9 = -9

25z² - 30z = -9

25(z² - (30/25)z = -9

25(z² - (6/5)z)/25 = -9/25

z² - 6/5 z = -9/25

• By completing the square

z² - (6/5)z +(-6/5•2•1)² = -9/25 +(-6/5•2•1)²

z² - (6/5)z +(-6/10)² = -9/25 +(-6/10)²

z² - (6/5)z +(-3/5)² = -9/25 +(-3/5)²

z² - (6/5)z +9/25 = -9/25 +9/25

• The left side of equation is now a perfect square

(z - 3/5)² = 0

√(z - 3/5)² = √0

z - 3/5 = 0

z - 3/5 + 3/5 = 3/5

z = 3/5

Answer:

273

Step-by-step explanation:

Nothing