Which of these graphs represents a function? Please help

Using the function concept, it is found that graph x represents a function.

A function is only represented if each value of the input only has one respective value of output.In a graph, for one value of x(horizontal axis), there can only be one respective value of y(horizontal axis).This can be verified applying the vertical line test. It is a function if the line crosses the function only once.In the appended image, it can be see that on graphs w, y, and z, the line crosses the function more than once, thus, they are not functions.Then, graph x is a function, as there are no points aligned vertically.

A similar problem is given at link

Top Right Graph is the only function.

Step-by-step explanation:

Imagine a vertical line moving from left to right over the entire width of the graph. If at any position, the line intersects more than one point on the graph, the graph is not a function. This is called the vertical line test.

The only graph that passes the vertical line test is the top right graph. All other graphs fail the vertical line test because a vertical line intersects more than one point at some position.

the desired equation is y = (3/5)x + 4

Step-by-step explanation:

Solving the given 5x + 3y = -21 for 3y yields  3y = -5x - 21.  Dividing all three terms by 3, we get:

y = (-5/3)x - 7, indicating that the given line has slope -5/3.

The slope of a line perpendicular to this y = (-5/3)x - 7 is 3/5, the negative reciprocal of -5/3.

Start with y = mx + b.  Substitute 1 for y, -5 for x and 3/5 for m.  Then:

1 = (3/5)(-5) + b, or

1 = -3 + b.  Then b must be 4, and so the desired equation is y = (3/5)x + 4.