1. Find the cost of levelling the ground in the form of a triangle having the sides 51 m, 37 m and 20 m at the rate of ₹ 3 per m².
a = 51 m, b = 37 m, c = 20 m
semiperimeter: p = (51+37+20):2 = 54 m
Area of triangle:

Rate: ₹ 3 per m².
Cost: ₹ 3•306 = ₹ 918
2. Find the area of the isosceles triangle whose perimeter is 11 cm and the base is 5 cm.
a = 5 cm
a+2b = 11 cm ⇒ 2b = 6 cm ⇒ b = 3 cm
p = 11:2 = 5.5

3. Find the area of the equilateral triangle whose each side is 8 cm.
a = b = c = 8 cm
p = (8•3):2 = 12 cm

4. The perimeter of an isosceles triangle is 32 cm. The ratio of the equal side to its base is 3 : 2. Find the area of the triangle.
a = 2x
b = 3x
2x + 2•3x = 32 cm ⇒ 8x = 32 cm ⇒ x = 4 cm ⇒ a = 8 cm, b = 12 cm
p = 32:2 = 16 cm

I think you meant to say n = 11. If so, then you are correct and it leads to the proper length for FG, which is 16 units. Nice work.
JKL should be the right answer
Step-by-step explanation:
Let the number be x.
ATQ,
Malachy halves the number and gets an answer of 67.3.

This the equation for the given statement.
It can also be written as :

Hence, this is the required solution.
Answer:
(x + 8)(x - 2)(4x - 1)
Step-by-step explanation:
Given that x = - 8 is a zero then (x + 8) is a factor
Divide f(x) by (x + 8) using Synthetic division
- 8 | 4 23 - 70 16
↓ - 32 72 - 16
---------------------------------
4 - 9 2 0
Quotient = 4x² - 9x + 2 = (x - 2)(4x - 1)
Thus
f(x) = (x + 8)(x - 2)(4x - 1)