To find the y-intercept of the equation y = -2.1x + 4.6, you simply set x to zero and solve for y.
Substitute x = 0 into the equation:
y = -2.1(0) + 4.6
y = 4.6
So, the y-intercept of the equation y = -2.1x + 4.6 is y = 4.6