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81x2 - 72x plus 16 is a perfect square trinomial true or false?
Wiki User
∙ 14y ago
If a trinomial is a perfect square, then the discriminant will equal 0. The discriminant is equal to B^2-4AC. The variables come from the standard form of a quadratic which is Ax^2+Bx+C
In this problem, A=81, B=-72, and C=16 so the discriminant is:
(-72)^2-4(81)(16)=5,184-5,184=0 so this is a perfect square trinomial.
To factor, notice that 81=9^2 and 16=4^2, so 81x^2=(9x)^2. We can then factor the trinomial into (9x+4)(9x-4)
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∙ 14y ago
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The square root of 81x squared?
sqrt(81x2)=9x*sqrt=square root of
Find the factorization of 81x2 plus 72x plus 16?
81x2 + 72x + 16 = 81x2 + 36x + 36x + 16 = 9x(9x + 4) + 4(9x + 4) = (9x + 4)2
Find the factorization 81x2 plus 72x plus sixteen?
Since the first and the last term happen to be perfect squares, you can take the square root of each, and check whether the linear term (the central term) happens to be twice the first term, times the last term. In this case it is.
The product of the sum and difference of the same two terms is equal to what?
For me, it is equal to the square of the first terms minus the square of the second terms...:-)For example . . .(9x + 5) (9x - 5)= (9x)2 - (5)2= 81x2 - 25The former answer was this:"it is equal to the square of the first term minus the square of the second term"If we answer in that way, the solution is this:(9x + 5) - (9x -5)= (9x + 5)2 - (9x - 5)2= (81x2 + 25) - (81x2 + 25)= 81x2 + 25 - 81X2 - 25= 0Let us use the DCMC or Dalope's Coefficient Method of Checking: (Checking the answer using only the coefficients)= (9 + 5) - (9 - 5)= (14) - (4)= 10Our answer to the problem (9x + 5) (9x - 5) using the "it is equal to the square of the first term minus the square of the second term" is 0 but the DCMC answer is 10. There is conflict with the answer!But if we answer in this way: "it is equal to the square of the first terms minus the square of the second terms" the answer would be 81x2 - 25 and it's answer in DCMC is 56. Let me prove it:(9 + 5) (9 - 5) (9 + 5) ( 9 - 5)= (14) (4) or = 81(9 x 9) - 25(5 x -5)= 56 = 56Conclusion: The only mistake in the former answer (it is equal to the square of the first term minus the square of the second term) is HIS SOLUTION TO HIS GIVEN EXAMPLE IS CORRECT BUT HIS ANSWER TO THE QUESTION "The product of the sum and difference of the same two terms is equal to what?" IS WRONG OR HE MISSED ONLY TO MAKE THE WORD "TERM" PLURAL!:-) I hope that my answer will correct your understanding about the above question guys!!!Jilverex Rainrex_rain@rocketmail.com
What is the product of 9 and x squared?
(9x)2 = 81x2
Find the factorization of 81x2-18x plus 1?
(9x - 1)(9x - 1)
What is the answer to 81x2 equals 49?
x2 = 49/81 so x = 7/9
How do you factor 81x2 126xy 49y2?
If that's + 49y2, the answer is (9x - 7y)(9x - 7y) or (9x - 7y)2
How do you factor 81x2-6-30?
There is a formula for the "difference of squares." In this case, the answer is 9(3x + 2)(3x - 2)
How do you factor 81x2-126xy 49y2?
If that's + 49y2, the answer is (9x - 7y)(9x - 7y) or (9x - 7y)2
How do you factor 81x2 18x 1?
If that's + 18x + 1, the answer is (9x + 1)(9x + 1) or (9x + 1)2
How can you check to see if the prime factorization you found for a number is correct?
You use the distributed property to find out if you have the same answer as you started out with. ex. 81x2+12t ...../....\..... ....9.....9...2....6 ..../\..../\.......|...... ...3..3.3.3xx.2....2.3t 3(27x2+2t) 3*27x2 3*2t 81x2+12t OR.. 9x2-1 = (3x+1)(3x-1) but to check it we multiple 3x and 3x to get 9x2 and theh 3x by -1 to get -3x then 1 by 3x to get positive 3x and then 1 and -1 to get a -1 so we end up with it looking like this 9x2-3x+3x-1 now since -3x+3x=0 we are left with the 9x2-1 the 9 needs to be multplied twice by the same number to get the number needed. so we have 9x2 needs to be broken up to 3x and 3x so that wen its multiplied we get 9x2 and for the -1.. we need to multiply the -1 by a positive 1 so that the can cancel out each other but we would get a -3x and a positive 3x that will cancel out each other to give us our final answer!
