Which of the equations are true identities? \begin{aligned} \text{A. }&(y+6)(y-7)+42=y^2-y \text{B. }&(x+3)(x-8)=x^2-5x \end{aligned} A. B. (y+6)(y−7)+42=y 2 −y (x+3)(x−8)=x 2 −5x

Only A, the first equation is true.

Step-by-step explanation:

A. (y + 6)(y – 7) + 42 = y² + 6y –7y – 42 + 42 = y² – y. This means A is true

B. (x + 3)(X – 8) = x² + 3x – 8x – 24 = x² – 5x – 24. This means B is false.

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so:

24

step-by-step explanation: