✔ 最佳答案
Hi Nikki...
The surest way to find the factors of your problems is to use the quadratic formula.. It will ease the burden of lengthy "trial and error" method.
The standard quadratic form of a trinomial is ax^2 + bx + c = 0
where;
a = coefficient of x^2
b = coefficient of x
c = constant
To get the two (2) values of x, x(-) and (x-) symbolized as x(±), you must substitute these coefficients and constant to the Quadratic formula;
x(±) = [- b ± (b^2 - 4ac)^(1/2)] /2a ---->>> QUADRATIC FORMULA
1. Given: a^2 + 28a + 27
Required: Factor:
Solution:
The standard form the given equation is a^2 + 28a + 27 = 0
Coefficients of a and constant:
A = 1
B = 28
C = 27
a(±) = [- B ± (B^2 - 4AC)^(1/2)] /2A
a(±) = {- 28 ± [(28)^2 - 4(1)(27)] }/2(1)
a(±) = {- 28 ± √676}/2
a(±) = {- 28 ± 26}/2
a(+) = (- 28 + 26)/2
a(+) = -2/2 = - 1 ------------>>> value of a(+)
a(-) = (- 28 - 26)/2
a(-) = - 54/2 = - 27 --------->>>> value of a(-)
thus, the factor of a^2 + 28a + 27 is;
(a + 1) (a + 27) -------->>>> answer
2. Given: (4p - 3)(5p + 1)
Required: Product
Solution:
(4p - 3)(5p + 1) = 20p^2 - 11p - 3 ------>>> Ans
3. Given: 2x^2 - 9x - 11
Required: Factor
Solution:
The standard form of the equation is;
2x^2 - 9x - 11 = 0
Coefficients of x and constant
a = 2
b = - 9
c = - 11
Substitute these to the the QUADRATIC FORMULA once again,
x(±) = [- b ± (b^2 - 4ac)]/2a
x(±) = {- ( -9) ± (- 9)^2 - 4(2)(-11)]^(1/2)}/2(2)
x(±) = {9 ± √169}/4
x(±) = {9 ± 13}/4
x(+) = (9 + 13)/4
x(+) = 11/2 ----------------->>> value of x(+)
x(-) = (9 - 13)/4
x(-) = - 1 --------------------->>> value of x(-)
thus, the factor of the given equation 2x^2 - 9x - 11 is
(x - 11/2) (x + 1)
or
(2x - 11) ( x + 1) ------------------->>> ans
4. Given: 8n^2 - 26n + 15
Required: Factor
solution:
The standard form of the given equation is;
8n^2 - 26n + 15 = 0
Coefficients of n and constant:
a = 8
b = - 26
c = 15
Substitute these to the QUADRATIC FORMULA;
n(±) = [- b ± (b^2 - 4ac)^(1/2)] /2a
n(±) = {- (-26) ± [(-26)^2 - 4(8)(15)^](1/2)} /2(8)
n(±) = {26 ± √196}/16
n(±) = {26 ± 14}/16
n(+) = (26 + 14)/16
n(+) = 5/2 ------------------>>>> value of n(+)
n(-) = (26 - 14)/16
n(-) = 12/16
n(-) = 3/4 ------------------>>>> value of n(-)
thus, the factor of 8n^2 - 26n + 15 is;
(n - 5/2) (n - 3/4)
or
(2n - 5) (4n - 3) ------------------->>>> ans
5. Given: 81k^2 + 36k + 4
Required: Factor
Solution:
The standard form of the given equation is;
81k^2 + 36k + 4 = 0
Coefficients of k and constant;
a = 81
b = 36
c = 4
Substitute these to the QUADRATIC FORMULA;
k(±) = [- b ± (b^2 - 4ac)^(1/2)] /2a
k(±) = {- 36 ± [(36)^2 - 4(81)(4)]} /2(81)
k(±) = {- 36 ± 0}/2(81)
k(+) = - 36/2(81)
k(+) = - 2/9 ----------------->>> value of k(+)
k(-) = - 2/9 ----------------->>> value of k(-)
thus, the factor of 81k^2 + 36k + 4 is;
(k + 2/9) (k + 2/9)
or
(9k + 2) (9k + 2) --------->>> ans
6. Given: (2y + 3)(2y - 3)
Required: find the Product
Solution:
(2y + 3)(2y - 3)
= 4y^2 - 9 -------------------->>>> ans