SOLUTION: Factor: z2 – 14z + 49 A) (z – 7)2 B) (z – 7)(z + 7) C) (z – 14)(z + 1) D) The expression is prime.

Algebra.Com
Question 140007: Factor: z2 – 14z + 49
A) (z – 7)2
B) (z – 7)(z + 7)
C) (z – 14)(z + 1)
D) The expression is prime.

Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!

Looking at we can see that the first term is and the last term is where the coefficients are 1 and 49 respectively.

Now multiply the first coefficient 1 and the last coefficient 49 to get 49. Now what two numbers multiply to 49 and add to the middle coefficient -14? Let's list all of the factors of 49:



Factors of 49:
1,7

-1,-7 ...List the negative factors as well. This will allow us to find all possible combinations

These factors pair up and multiply to 49
1*49
7*7
(-1)*(-49)
(-7)*(-7)

note: remember two negative numbers multiplied together make a positive number


Now which of these pairs add to -14? Lets make a table of all of the pairs of factors we multiplied and see which two numbers add to -14

First NumberSecond NumberSum
1491+49=50
777+7=14
-1-49-1+(-49)=-50
-7-7-7+(-7)=-14



From this list we can see that -7 and -7 add up to -14 and multiply to 49


Now looking at the expression , replace with (notice adds up to . So it is equivalent to )




Now let's factor by grouping:


Group like terms


Factor out the GCF of out of the first group. Factor out the GCF of out of the second group


Since we have a common term of , we can combine like terms

So factors to


So this also means that factors to (since is equivalent to )


note: is equivalent to since the term occurs twice. So also factors to


-------------------------------
Answer:

So factors to

RELATED QUESTIONS

3/z+7 + 24/z^2+6z-7 A) 24/(z-1)(z+7) B)3/(z-1) C)3(z-1)/z+7... (answered by MathLover1)
OUCH!.. Factor and match your result to the correct answer below. z2 – 12wz + 13w2 A)... (answered by stanbon)
comp;etely factor the expression 7(x-y)-z(x-y) a. (x-y)(7-z) b. (x-y)^2(7-z)^3 c.... (answered by jim_thompson5910)
can someone please show me how to do this problem: Use the Gauss-Jordan method to... (answered by stanbon)
(7z^2 + 7z/ 4z +8) x (z^2 -4/ z^3 +2z^2 + z) A) 7(z-2)/4(z+1) B) 7(z+2)/4(z-1) C) (answered by richwmiller)
Write each algebraic fraction given in its lowest terms: (8z-56) (z^2-7z) A)8/z-7 -... (answered by josgarithmetic)
divide and simplify z^2-49/z /z+7/z+9 this is a fraction divided by a fraction (answered by jim_thompson5910)
solve the following equation 3/z-3 + 5/z-1 = 8/z-2 A) z=-4 B) z=-6 C) z=4 D)... (answered by edjones)
It's on Rational Expressions. z2-49 -------... (answered by sophxmai)