Answer:
Second option: 81y^4 - 16x^2, the difference of squares
Step-by-step explanation:
(9y^2-4x)(9y^2+4x) is a special product named difference of squares, then we can apply this formula:
(a-b)(a+b)=a^2-b^2, with a=9y^2 and b=4x, then:
(9y^2-4x)(9y^2+4x)=(9y^2)^2 - (4x)^2
(9y^2-4x)(9y^2+4x)=(9)^2 (y^2)^2 - (4)^2 (x)^2
(9y^2-4x)(9y^2+4x)=81y^(2*2) - 16x^2
(9y^2-4x)(9y^2+4x)=81y^4 - 16x^2
So, 10%-7%=3%=$294
$294/3%=$9800
Answer: The cost price of the necklace is $9800.
<h2>The chances of receiving two greens are 5/31.</h2>
<em>Given a bag containing four blue, three red, and five green marbles, the total result is:</em>
<em>Total number of balls = 4 + 3 + 5 = 12</em>
<em>If green is chosen first, the chances of picking a green are 5/12.</em>
<em>The probability that the second stone is green is 4/11 if it is picked and not replaced (4 greens remaining)</em>
<em>The chance of earning two greens is 5/12 4/11.</em>
<em>The chance of getting two greens is 20/132.</em>
<em>The chance of earning two greens is 5/31.</em>
<h3>
<em>As a result, the chance of getting two greens is 5/31.</em></h3>
