Answer:
B. 7x - 5
Explanation
Given the expression 21x^2 + 13x – 20, to get which of the given expression is a factor we will have to factorize the equation first as shown;
21x^2 + 13x – 20
= 21x^2 + 28x - 15x - 20
= 7x(3x+4) -5(3x+4)
= (7x-5)(3x+4)
Hence one of the factors is 7x - 5
First, we need to get the variable by it self.
-2x+6=20
-6=-6
-2x=14
Next, since the operation is multiplication, we need to divided both sides by -2.
X=-7
(9-3)4
The cake had 24 pieces
It can be expressed as a fraction with integer numerator and denominator, so it's a rational number.
