Whats the factoring of a^2-6a-21=-5 ?

So before we can factor this equation, we first have to set the equation to zero. To do this, add 5 on both sides of the equation:

Next, I am going to be factoring by grouping. Firstly, what two terms have a product of -16a² and a sum of -6a? That would be -8a and 2a. Replace -6a with 2a - 8a:

Next, a² + 2a and -8a - 16 separately. Make sure that they have the same quantity on the inside of the parentheses:

Now you can rewrite this equation as , which is your final answer.

+25 = x

step-by-step explanation:

here x is the hypotenuse of a right triangle whose legs are 7 and 24.   by the pythagorean theorem, 7² + 24² must equal x²:

x² = 49 + 576 = 625.   thus, x = +√625 = +25 = x

its not b

step-by-step explanation: