Thirty-five less than the square of a number is the same as 2 times the number. Find the number

9514 1404 393

  -5  or  7

Step-by-step explanation:

Let x represent the number. The problem statement tells us ...

  x^2 -35 = 2x

  x^2 -2x -35 = 0 . . . . subtract 2x to put in standard form

  (x -7)(x +5) = 0 . . . . . factor

  x = 7  or  x = -5 . . . . solutions are values of x that make the factors zero

The number could be either -5 or +7.

< xcy ≅ < xby

step-by-step explanation:

in δcax and δbax,

so, δcax ≅ δbax (side-angle-side or sas)

since δcax ≅ δbax, we can conclude < acx ≅ < abx

in δacy and δaby,

so, δacy ≅ δaby (side-angle-side or sas)

since δacy ≅ δaby, we can conclude < acy ≅ < aby

now,

< acy ≅ < aby

=> < acx + < xcy ≅ < abx + < xby

=> < acx + < xcy ≅ < acx + < xby   (since < acx ≅ < abx already proved above)

subtracting < acx from both sides, we get

< acx + < xcy -< acx ≅ < acx + < xby -< acx

cancelling out < acx and -< acx from both sides, we get

< xcy ≅ < xby (proved)