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Which of the following vectors are orthogonal to (2,1)? check all that apply

240 seventh graders and two-thirds of the students participate in after-school activities how many students participate in after-school activities

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.