Solve Quadraticequations X(5x-9)=2 Tiger Algebra Solver

Rearrange:

Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation : x*(5*x-9)-(2)=0

Step by step solution :

Step 1 :

Equation at the end of step 1 :

x • (5x - 9) - 2 = 0

Step 2 :

Trying to factor by splitting the middle term

2.1 Factoring 5x2-9x-2 The first term is, 5x2 its coefficient is 5 .The middle term is, -9x its coefficient is -9 .The last term, "the constant", is -2 Step-1 : Multiply the coefficient of the first term by the constant 5 • -2 = -10 Step-2 : Find two factors of -10 whose sum equals the coefficient of the middle term, which is -9 .

-10

+

1

=

-9

That's it

Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, -10 and 1 5x2 - 10x + 1x - 2Step-4 : Add up the first 2 terms, pulling out like factors : 5x • (x-2) Add up the last 2 terms, pulling out common factors : 1 • (x-2) Step-5 : Add up the four terms of step 4 : (5x+1) • (x-2) Which is the desired factorization

Equation at the end of step 2 :

(x - 2) • (5x + 1) = 0

Step 3 :

Theory - Roots of a product :

3.1 A product of several terms equals zero.When a product of two or more terms equals zero, then at least one of the terms must be zero.We shall now solve each term = 0 separatelyIn other words, we are going to solve as many equations as there are terms in the productAny solution of term = 0 solves product = 0 as well.

Solving a Single Variable Equation :

3.2 Solve : x-2 = 0Add 2 to both sides of the equation : x = 2

Solving a Single Variable Equation :

3.3 Solve : 5x+1 = 0Subtract 1 from both sides of the equation : 5x = -1 Divide both sides of the equation by 5: x = -1/5 = -0.200

Supplement : Solving Quadratic Equation Directly

Solving 5x2-9x-2 = 0 directly

Earlier we factored this polynomial by splitting the middle term. let us now solve the equation by Completing The Square and by using the Quadratic Formula

Parabola, Finding the Vertex :

4.1 Find the Vertex of y = 5x2-9x-2Parabolas have a highest or a lowest point called the Vertex . Our parabola opens up and accordingly has a lowest point (AKA absolute minimum) . We know this even before plotting "y" because the coefficient of the first term, 5 , is positive (greater than zero).Each parabola has a vertical line of symmetry that passes through its vertex. Because of this symmetry, the line of symmetry would, for example, pass through the midpoint of the two x -intercepts (roots or solutions) of the parabola. That is, if the parabola has indeed two real solutions.Parabolas can model many real life situations, such as the height above ground, of an object thrown upward, after some period of time. The vertex of the parabola can provide us with information, such as the maximum height that object, thrown upwards, can reach. For this reason we want to be able to find the coordinates of the vertex.For any parabola,Ax2+Bx+C,the x -coordinate of the vertex is given by -B/(2A) . In our case the x coordinate is 0.9000 Plugging into the parabola formula 0.9000 for x we can calculate the y -coordinate : y = 5.0 * 0.90 * 0.90 - 9.0 * 0.90 - 2.0 or y = -6.050

Parabola, Graphing Vertex and X-Intercepts :

Root plot for : y = 5x2-9x-2 Axis of Symmetry (dashed) {x}={ 0.90} Vertex at {x,y} = { 0.90,-6.05} x -Intercepts (Roots) : Root 1 at {x,y} = {-0.20, 0.00} Root 2 at {x,y} = { 2.00, 0.00}

Solve Quadratic Equation by Completing The Square

4.2 Solving 5x2-9x-2 = 0 by Completing The Square . Divide both sides of the equation by 5 to have 1 as the coefficient of the first term : x2-(9/5)x-(2/5) = 0Add 2/5 to both side of the equation : x2-(9/5)x = 2/5Now the clever bit: Take the coefficient of x , which is 9/5 , divide by two, giving 9/10 , and finally square it giving 81/100 Add 81/100 to both sides of the equation : On the right hand side we have : 2/5 + 81/100 The common denominator of the two fractions is 100 Adding (40/100)+(81/100) gives 121/100 So adding to both sides we finally get : x2-(9/5)x+(81/100) = 121/100Adding 81/100 has completed the left hand side into a perfect square : x2-(9/5)x+(81/100) = (x-(9/10)) • (x-(9/10)) = (x-(9/10))2 Things which are equal to the same thing are also equal to one another. Since x2-(9/5)x+(81/100) = 121/100 and x2-(9/5)x+(81/100) = (x-(9/10))2 then, according to the law of transitivity, (x-(9/10))2 = 121/100We'll refer to this Equation as Eq. #4.2.1 The Square Root Principle says that When two things are equal, their square roots are equal.Note that the square root of (x-(9/10))2 is (x-(9/10))2/2 = (x-(9/10))1 = x-(9/10)Now, applying the Square Root Principle to Eq. #4.2.1 we get: x-(9/10) = √ 121/100 Add 9/10 to both sides to obtain: x = 9/10 + √ 121/100 Since a square root has two values, one positive and the other negative x2 - (9/5)x - (2/5) = 0 has two solutions: x = 9/10 + √ 121/100 or x = 9/10 - √ 121/100 Note that √ 121/100 can be written as √ 121 / √ 100 which is 11 / 10

Solve Quadratic Equation using the Quadratic Formula

4.3 Solving 5x2-9x-2 = 0 by the Quadratic Formula . According to the Quadratic Formula, x , the solution for Ax2+Bx+C = 0 , where A, B and C are numbers, often called coefficients, is given by : - B ± √ B2-4AC x = ———————— 2A In our case, A = 5 B = -9 C = -2 Accordingly, B2 - 4AC = 81 - (-40) = 121Applying the quadratic formula : 9 ± √ 121 x = ————— 10Can √ 121 be simplified ?Yes! The prime factorization of 121 is 11•11 To be able to remove something from under the radical, there have to be 2 instances of it (because we are taking a square i.e. second root).√ 121 = √ 11•11 = ± 11 • √ 1 = ± 11 So now we are looking at: x = ( 9 ± 11) / 10Two real solutions:x =(9+√121)/10=(9+11)/10= 2.000 or:x =(9-√121)/10=(9-11)/10= -0.200

Two solutions were found :

1. x = -1/5 = -0.200
2. x = 2