Algebra HOMEWORK HELP?! Please & thanks.

Thanks! If you answer these correctly I will love you forever. 1. If the slope of a straight line is -5 and if X (the variable on the horizontal axis) increases by 10, then Y (the variable on the vertical axis) will: a) decrease by .5 b) increase by .5 c) decrease by 50 d) increase by 50 e)... Show More

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  • 1-) c

    Because, a slope of "-5" means y = -5x (plus a constant, but that is irrelevant right now).

    Insert "10" to the position of x. What do you get?

    y = -5(10)

    y = -50

    Decreases by 50.

    2-) c (this time you insert the variable to y, but everything else is same)

    3-) d (same tactic)

    4-) e

    Basically, y increases by 4850 - 1730 = 3120 when x increases by 500 - 100 = 400.

    If y increases by 3080 and x increases by 400, then the slope of the line is 3120 / 400 = 7.8

    Meaning that the equation should look like this:

    Y = 7.8C + k (k is your y-intercept - the point where the line intersects with the vertical axis - and that is not given in the question so I can't tell you what k is, but we might not need it at all.)

    None of the answers have the "7.8C" expression, so the correct answer must be "e - none of the above".