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    Graphing, Inequalities, slopes, Variables, and Elimination

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    Please see attached. help with homework. equation, graphs.

    © BrainMass Inc. brainmass.com October 10, 2019, 1:46 am ad1c9bdddf
    https://brainmass.com/math/graphs-and-functions/graphing-inequalities-slopes-variables-elimination-348485

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    #1. Multiply 6/7 * -1/5
    -6/35

    #2. Simplify -5[-25-(29-31)]
    -5[-25-(-2)]
    -5(-23)
    115

    #3 solve 0.3x<-24
    x<-80
    #4 solve y-7>-18
    y>-11
    #5 find the slope of (-4,0) (0,1)
    m=dy/dx
    m=(0-1)/(-4-0)
    m=1/4
    #6 graph x + 5y=10
    Change to y=mx+b
    5y=-x+10
    y=(-1/5)x+2

    #7 trains A and B are traveling in the same direction on parallel tracks. Train A is traveling 60 mph and train B is traveling 64mph. Train A passes a station at 3:20pm. If train B passes the same station at 3:50pm at what time will train A catch up to train B?
    We need to figure out how much time it will take for those 4mph faster to catch up to a 30 minute head start. I assume we want to know how long it will take for B to catch A, not the other way around.

    Train A gets a 30 minute headstart, allowing it to move 30 miles ahead. Train B, in order to fill this gap, is basically moving at 4 mph compared to Train A. So we take 30 miles and divide by 4 mph, getting 7.5 hours. So 7.5 hours after Train B passes the station, it catches train A. 3:50 + 7:30 = 11:20PM

    #8 translate to an algebraic expression The product of 45% and some number
    0.45*x

    #9 is the coordinates a function (-3,7) (2,2) (3,1) (7,5)
    Yes
    We know this because none of the x values are repeated, and none of the y values are repeated
    #10 solve by substitution 8x+9y=-47 x=-5-2y
    8(-5-2y)+9y=-47
    -40-16y+9y=-47
    -40-7y=-47
    -7y=-7
    y=1
    x=-5-2
    x=-7
    (-7,1)
    #11 find ...

    Solution Summary

    49 problems dealing with elimination, graphing, inequalities, finding slopes, percentages, word problems, and solving for variables. A tour de force of different techniques!

    $2.19