Prove that the bisectors of two supplementary angles are perpendicular to each other.

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

Haruka hiked several kilometers in the morning. she hiked only 66 kilometers in the afternoon, which was 25% less than she had hiked in the morning. how many kilometers did haruka hike in all?

If a seller prepaid the taxes of $4,400 and the closing is set for may 19, using the 12 month/30 day method what will the buyer owe the seller as prorated taxes?