X=15. This is the Altitude theorem which is Altitude/Part = Altitude/Other part. In this question you would set up the proportion 9/X = X/25 and multiply cross products to get 225=X^2. Then you undo X^2 by doing the square route of 225 and then you get 15 as the final answer.
While there are many quadratic equations using -6 and 5 as roots, the most simple would be the basic (x+6)(x-5)=0, or simplified, x² + x - 30 = 0.
Using these roots, all you have to do is make both sides of the equation and even both sides of the multiplied pre-product to equal 0. If using this format, x has to be equal to -6, and 5.
Answer:
it equal 2400
but in an easier and a faster u can just
do 30
x80
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hide number 8 put down the zero then hide the zero in the 80 and multiply normaly
