1. f(x) = 9x² + 6x - 8
f(x) = (3x - 2)(3x + 4)
When (3x - 2) = 0, then x = 2/3
When (3x + 4) = 0, then x = -4/3
Answer: The zeros are two divided by three and negative four divided by three.
2. f(x) = 9x³ - 45x² + 36x
f(x) = 9x(x² - 5x + 4)
= 9x(x - 1)(x - 4)
When 9x = 0, then x = 0
When (x-1) = 0, then x = 1
When (x-4) = 0, then x = 4
Answer: 0, 1 and 4
3. f(x) = 4(x+7)²(x-7)³
When (x+7)² = 0, then x = -7 (twice)
When (x-7)³ = 0, then x = 7 (thrice)
Answer: 7, multiplicity 2; -7 multiplicity 3
4. The zeros of f(x) are √5, -√5, -7
The factors of f(x) are (x-√5)(x+√5)(x+7)
Note that (x-√5)(x+√5) = x² - (√5)² = x² - 5
f(x) = (x²-5)(x+7)
= x³ + 7x² - 5x - 35
Answer: f(x) = x³ + 7x² - 5x - 35
5. Expand (2x + 4)³
From Pascal's Triangle, the coefficients are 1 3 3 1
Therefore
(2x + 4)³ = 1(2x)³(4)⁰ + 3(2x)²(4)¹ + 3(2x)¹(4)² + 1(2x)⁰(4)³
= 8x³ + 48x² + 96x + 64
Answer: 8x³ + 48x² + 96x + 64
One sixth of 60km would be 10km.
<span><u><em>The correct answer is:</em></u>
2.
<u><em>Explanation</em></u><span><u><em>:</em></u>
20 hundreds =20*100=2000;
this is two thousand, so it is made of 2 thousands.</span></span>
2 pounds ---- 100%
x pounds -----18%
x=(2*18)/100=36/100=0.36 pounds
