Method to solve binomials of second degree, Mathematics

Assignment Help:

In this part we look at another method to obtain the factors of an expression. In the above you have seen that x2 - 4x + 4 = (x - 2)2 or (x - 2)(x - 2). If you observe it carefully we find that the middle number - 4 is the sum of -2 and -2 and the last term 4 is the product of -2 and -2. That is, if you think that so and so number might be the factors of the binomial those numbers should satisfy this condition. We take another example. You are given x2 + 15x + 56 and asked to factorize it. Now if you think that, say, 6 and 7 are the factors of this expression then their product should be equal to 56 and their sum should be equal to 15. However in this case we observe that the product is 42 and the sum is 13. Therefore, 6 and 7 cannot be the factors of this expression. Now try 7 and 8. We find that their product is 56 and the sum 15. That is, 7 and 8 are the factors of the given expression. This can be clarified by multiplying (x + 8) and (x + 7).

One point to which we have to pay attention is that we have to take even signs into consideration. For instance, consider an expression x2 - 17x + 70. What could be the factors of this expression? Let us try 7 and 10. No doubt, the product is 70 and the sum 17. Still these cannot be the factors of the given expression, because the sum is -17 and we got only 17. Now let us try -7 and -10. The sum of these two numbers gives us -17 and their product as 70. This is what we require. Therefore, the factors are x - 7 and x - 10 (observe that in this case if we took x = -7 and         x = -10, we would have got the factors as x + 7 and x + 10, whose multiplication would give us x2 + 17x + 70 and not x2 - 17x + 70. That is, the values should be considered as they are). Now let us consider an expression x2 - 3x - 70. Let us try 7 and -10 for this expression. The sum of these two values is -10 + 7  = -3 and the product being -70. That is, x + 7 and x - 10 are two factors of the given expression and not x - 7 and x + 10.


Related Discussions:- Method to solve binomials of second degree

Prove that ac2 =ab2 + bc2+2bcxbd, If ABC is an obtuse angled triangle, obtu...

If ABC is an obtuse angled triangle, obtuse angled at B and if AD⊥CB Prove that AC 2 =AB 2 + BC 2 +2BCxBD Ans:    AC 2 = AD 2 + CD 2 = AD 2 + (BC + BD) 2 = A

Least common denominator, Let's recall how do to do this with a rapid numbe...

Let's recall how do to do this with a rapid number example.                                                     5/6 - 3/4 In this case we required a common denominator & reme

digraph of r, Let R be the relation on S = {1, 3, 6, 9, 27} defined by aRb...

Let R be the relation on S = {1, 3, 6, 9, 27} defined by aRb iff a|b. (a) Write down the matrix of R. (b) Draw the digraph of R. (c) Explain whether R is reflexive, irrere

Volume of prisms, How did the teacher get 30 + 12 + 1.5 for the equation of...

How did the teacher get 30 + 12 + 1.5 for the equation of volume of rectangular prism measuring L=14.4, W= 3, and H= 5? Formula given was V= Bh. My answer was 43.5.14.5 x 3.

Parametric equations and polar coordinates, Parametric Equations and Polar ...

Parametric Equations and Polar Coordinates In this part we come across at parametric equations and polar coordinates. When the two subjects don't come out to have that much in

Proportions, bananas are on sale for 3 pounds for $2. At that price how man...

bananas are on sale for 3 pounds for $2. At that price how many pounds can you buy for $22

Unitary Method Sample Questions, Where can I find sample questions of Unita...

Where can I find sample questions of Unitary Method for kids to practice? I need  Unitary Method  study material if availbale here on website, i found there is very useful material

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd