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) do none of the above

2. The slope of a straight line is -2. If Y (the variable on the vertical axis) increases by 4, then X (the variable on the horizontal axis) will:

a) increase by 2

b) increase by 8

c) decrease by 2

d) decrease by 8

e) none of the above

3. The slope of a straight line is -8. if Y (the dependent variable on the vertical axis) increases by 4, then X (the independent variable on the horizontal axis) will:

a) increase by 2

b) decrease by 2

c) increase by 1/2

d) decrease by 1/2

e) increase by -8

4. Consider the graph of the relationship between consumption, C, and income, Y, in the graph directly above. Assume consumption depends on income. What is the equation of consumption in terms of income? And the graph has points at (100, 1730) and (500, 4850)

a) c=.78Y

b) Y=950+.78C

c) C=950+.975Y

d) Y=1000+1.28C

e) none of the above correctly represent the equation of consumption in terms of income


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Most Helpful Guy

  • 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".

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