In the xy-plane, line m has the equation y=-5x+a, where a is a constant. Line n passes through the origin and is perpendicular to line m. If line m and line n intersect at the point (15,b), where b is a constant, what is the value of a ?



Comments (1)

Can’t you also solve this without using/ solving for “b”?

For instance, I find the equation of line n being y=1/5x + 0
Then set y=1/5x equal to y=-5x+a so that it results in: 1/5x = -5x+a
I then plug 15 into x and solve for “a”. That way, I don’t have to worry about “b” because I eliminated it when I set the two equations equal to each other.

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