Question 63920This question is from textbook introductory and intermediate algebra
: m^2-8m+15=0
This question is from textbook introductory and intermediate algebra
Found 2 solutions by rahman, praseenakos@yahoo.com:
Answer by rahman(247)   (Show Source):
Answer by praseenakos@yahoo.com(507)  (Show Source):
You can put this solution on YOUR website! ANSWER:
m^2-8m+15=0
ANSWER;
This is a quadratic equation in the variable,' m'
WE CAN SOLVE THIS PROBLEM USING DIFFERENT METHODS.
1. SPLITTING MIDDLE TERMS
2. USING QUADRATIC FORMULA
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Lets take the first method,
m^2-8m+15=0, here we have coefficent of m is -8 and the consant term is +15
Find out two numbers so that their product(multiplication) is +15 and their sum is -8
such two numbers are -3 and -5
because -3* -5 = +15 and -3 + -5 = -8
Now split the middle term as follows,
m^2 - 5m - 3m + 15 = 0
Now group the terms as follows,
(m^2 - 5m )- (3m - 15) = 0
Take out common terms from each group,
m ( m - 5 ) - 3 ( m - 5 ) = 0
again (m-5) is common in both the groups, so take them out,
(m-5)(m -3) = 0
This implies, either (m-5) is equal to 0 or (m -3) = 0
If (m-5) = o
==> m = 5 and
If(m -3) =0 ==> m = 3
Thos we got two values for m.
Whichj is the required solutions for the given equation.
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Now lets take the second method,
We have the quadratic formula,
 for solving a standard quadratic equation, ax^2 + bx + c = 0
Compare this with our given equation,
then we have ,
a= 1, b = -8 and c= 15
substitute these values in the quadratic formula,
That means m = (8 + 2)/(2) or m = (8 - 2)/(2)
==> m = 10/2 or m = 6/2
==> m = 5 or m = 3
Here also we got the same value.
You can use any method which you find easier.
Hope you understood.
Regards.
praseenakos@yahoo.com
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