factor this expression
-21x+28
a. -7(3x-4)
b. -7(3x+4)
c. 7(3x-4)
d. -(21x-4)
The correct answer is: b. -7(3x+4)
To factor the expression -21x + 28, we need to find the greatest common factor of the terms -21x and 28, and then divide both terms by it.
The greatest common factor of -21x and 28 is 7.
So, by dividing both terms by 7, we have:
(-21x + 28)/7
Simplifying further, we get:
-3x + 4
Therefore, the factored form of the expression -21x + 28 is:
-7(3x - 4)
Hence, the correct answer is option (a) -7(3x - 4).
To factor the expression -21x + 28, we need to find the greatest common factor (GCF) of the terms in the expression. In this case, the GCF is 7.
Now we can rewrite the expression as follows:
-21x + 28 = 7(-3x + 4)
So, the factored form of the expression -21x + 28 is -7(3x - 4).
Therefore, the correct answer is option a: -7(3x - 4).