Im pretty sure its distribution property.
It has zero solutions because when u subtract z to the other side u get nothing which equals to 2
The slope of the parallel line is -6/7
the slope of the perpendicular line is 7/6
the slope of the line = -6/7
the gradient of two parallel lines are equal
the product of the gradient of two perpendicular lines is -1
: the gradient m1*m2 = -1
m2= -1(-6/7)
m2= 7/6
Y = 2x-3
x + y = 18
Since you already know what y is equal to, we can plug that in into the second equation.
x + (2x-3) = 18
x + 2x -3 = 18
3x -3 = 18
Add 3 to both sides of the equation. (By doing this, we can isolate the 3x on the left side by getting rid of the -3)
3x = 21
Divide 3 on both sides
x = 7