how do we solve this equation graphically?

x+y=4

y=1+x

(graphical solution of simultaneous equation)

Update:

how do we solve 3x+2y=9

2x-2y=3

in graphical solution in simultaneous equation?

6 Answers

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  • Lauren
    Lv 5
    1 decade ago
    Favorite Answer

    get y alone in the first equation, graph them on a graphing calculator, and then see where they intersect

  • 1 decade ago

    Both equations are straight lines.

    Graph them. (you need only 2 points to graph)

    Intersection point is the solution.

    x+y=4

    When x=0, y=4, (0,4)

    When y=0, x=4 (4,0)

    Plot these 2 points, draw your line through them.

    y=1+x

    When x=3, y=4 (3,4)

    When x=7, y=8 (7,8)

    Plot these 2 points, draw your line

    The 2 lines intersect at (3/2,5/2). That's the solution.

    To graph a straight line, you need only 2 points.

    You find these points by choosing any number you

    wish for x or y, plug it into the equation, find the other

    variable.

    It is easiest to pick x=0, find y, then pick y=0, find x.

    That's how I did the first line.

    As I said though, you can pick any number you wish.

    That's how I did the second line.

  • 1 decade ago

    write each in standard form:

    y = -x + 4

    y = x + 1

    those are your 2 lines. the first line has a y intercept of 4, and a slope of -1. so your first point is at (0,4) and you can find your 2nd point by setting y = 0 and solving for x.

    0 = -x + 4

    x = 4

    so your 2nd point is (4,0). then, simply connect those 2 points and you have your first line.

    do the same thing for the 2nd line. your first point is (0,1), and your 2nd point is found the same way as above

    0 = 1+ x

    x = -1

    so your 2nd point is (-1,0)

    now draw the 2nd line (on the same graph as the 1st line). the answer to the problem is the point at which the 2 lines intersect, or (3/2, 5/2).

  • 1 decade ago

    X=3/2

    Y=5/2

    GRAPHICALLY YOU SHOULD BUILD THE GRAPHICS FOR:

    Y=4-X AND FOR Y=X+1 AND SEE WHERE THEY MEET

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  • Anonymous
    4 years ago

    combine like words and set such as 0 x^2+3=0 set up a T-chart w/x&y, plug in numbers (-5,-2,0,2,5) for X and get your Y value. you will graph an upward putting out parabala

  • 1 decade ago

    First, you can manipulate x+y=4 into y=4-x , then you can find where the lines intersect to find your x value.

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