Etermine which of the following subsets of R3×3 are subspaces of R3×3. 1. The singular 3×3 matrices 2. The 3×3 matrices whose entries are all integers 3. The symmetric 3×3 matrices 4. The 3×3 matrices with all zeros in the first row 5. The invertible 3×3 matrices 6. The 3×3 matrices with trace 0 (the trace of a matrix is the sum of its diagonal entries) 7. The upper triangular 3×3 matrices 8. The 3×3 matrices in reduced row-echelon form

idk this answer sorry cant on this one.

step-by-step explanation:

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

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mrb

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answer: the distance

step-by-step explanation:

to calculate the distance d of a line segment with endpoints (x1, y1) and (x2, y2) use the formula d (x2 x1)2 (y2 y1)2. to calculate the midpoint of a line segment with endpoints (x1, y1) and (x2, y2) use the formula