Answer:
a = -

Explanation:
the equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
y = 2x - 3 ← is in slope- intercept form
with slope m = 2
given a line with slope m then the slope of a line perpendicular to it is
= -
= -

Thus the value of a in the equation y = ax + 2 is a = -
