51 is 4 times a number of books less 13

16 books

Step-by-step explanation:

We need to translate this word equation to algebraic equation.

We want to find the number of books. Let it be "x".

Also, note "is" means "=".

51 is 4 times, would translate to:

51 = 4 *

a number of books LESS 13, would translate to:

x - 13

Combining, we get:

51 = 4*x - 13

We can now solve for x:

So, the number of books = 16

c. 27 units.

step-by-step explanation:

we are told that in circle a, ∠bae ≅ ∠dae.

we can see from our given diagram that in and ;

, as these are radii of our given circle.

therefore, by sas congruence postulate.

hence, side be will be equal to side de as corresponding parts of congruent triangles are congruent. so we can set an equation to find the value of x as:

now let us substitute x=17 in the expression for the length of be.

therefore, length of be will be 27 units and option c is the correct choice.