This is a parabola, first, locate the line of symmetry.
the line of symmetry is x=-b/2a
in this case, b=-2, a=-1, so the line of symmetry is x=-1
when x=-1, f(x)=-(-1)²-2(-1)-3=-2
locate the point (-1,-2) on the grid. this point is the vertex.
get two pairs of points with x=-1 as the symmetry line:
(0, -3) and (-2, -3); (1,-6) and (-3,-6)
connect these five points into a parabola, stick out at the ends because it will extend forever downward.
|3+10|=|3|+|10|
|13|=|13|
13=13
A, C. A is obviously correct because it’s the e same thing and C you combine like terms (2n+n=3n,2+4=6,=3n+6) it’s not B because it’s not 18, it’s not D because you’d get 3n+18 and it’s not E because you’d get 3n+12, meaning the only correct answers are A and C
10r² + 3 = 813
10r² = 813 - 3
10r² = 810
r² = 810 ÷ 10
r² = 81
r = √81
r = <u>9</u>
So, the value of <em>r </em>is 9
<em>Hope </em><em>it </em><em>helpful </em><em>and </em><em>useful </em><em>:</em><em>)</em>
