Elga’s age is 40 and Alvin’s age is 54
The equation given in the question has two unknown variables in the form of "x" and "y". The exact value of "x" and "y" cannot be determined as two equations are needed to get to the exact values of "x" and "y". This equation can definitely be used to show the way for determining the values of "x" in terms of "y"and the value of "y" in terms of "x". Now let us check the equation given.
2x - 5y = - 15
2x = 5y - 15
2x = 5(y - 3)
x = [5(y - 3)]/2
Similarly the way the value of y can be determined in terms of "x" can also be shown.
2x - 5y = - 15
-5y = - 2x - 15
-5y = -(2x + 15)
5y = 2x + 15
y = (2x +15)/5
= (2x/5) + (15/5)
= (2x/5) + 3
So the final value of x is [5(y -3)]/2 and the value of y is (2x/5) + 3.
y = mx + b
To find the slope(m), you use the slope formula:

You plug in the points into the equation.


The slope is 0
y = 0x + b
Any number multiplied by 0 is 0. So:
y = b
To find b, you plug in the y value of either of the points.
-4 = b
Your equation is:
y = -4 (This is a horizontal line)