Answer:
36x² - 9y²
Step-by-step explanation:
We see that the given expression (6x + 3y)(6x - 3y) looks just like the expression (a + b)(a - b). When multiplied out, this is a difference of squares identity that I highly recommend you memorise:
(a + b)(a - b) = a² - b²
Here, a = 6x and b = 3y, so plug these in:
(6x + 3y)(6x - 3y) = (6x)² - (3y)² = 36x² - 9y²
Yes you have the correct answers for each of the four problems. Nice work.
For anyone curious,
rd = removable discontinuity
id = infinite discontinuity
c = continuous
Answer:
Sol: In this question, firstly we have to make the first bracket as a complete square of the second bracket. This we can by adding 2.x.1/x which is equivalent to 2. Then the equation becomes:
6(x2 + 1/x2 +2) – 5(x + 1/x) = 50 { 38 + 6*2)
⇒ 6(x2 + 1/x2 +2) – 5(x + 1/x) – 50 = 0
Now put x + 1/x = y
⇒ 6y2 -5y -50 = 0
⇒ (2y +5)(3y-10)= 0
⇒ y=-5/2 or 10/3
As x is positive therefore, x + 1/x =10/3
On solving further you will get as x=3 or 1/3
Answer:
D.
Step-by-step explanation: