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Area of a circle is 75 cm².
Area of a circle is computed by multiplying pi to the square of the radius.
A = πr²
diameter = 10 cm
radius = d/2 = 10/2 = 5 cm
pi = 3
A = 3(5cm²)
A = 3(25cm²)
A = 75 cm²
You weren't clear on instructions
X^2-9x=-8
x^2-9x+8=-8+8
x^2-9x+8=0
(x-8)(x-1)=0
x-8=0
x-8+8=0+8
x=8
x-1=0
x-1+1=0+1
x=1
There are 2 solutions, which are 1 and 8