Question 5353
m²- 2m - 63 = 0
You need to find 2 numbers whose sum is -2 and whose product is -63. A way to do that is to express 63 in its prime factors. 3*3*7. Now use these factors in different combination and you´ll find the 2 numbers you need. In this case the numbers are 9 (3*3) and 7(7). So, -9+7= -2 and -9*7= -63.
Now you can solve the equation as follows:
m²-9m +7m -63=0 Now you need to factor
m(m-9)+7(m-9)=0
(m-9)(m+7)=0
m-9=0, m=9
m+7=0, m= -7
The solution set is {-7,9}