Final answer:
To find the y-intercept of the equation, substitute x=0 and solve for y.
Step-by-step explanation:
The y-intercept can be found by setting x=0 in the equation and solving for y. In the equation 21x - y = 23, substituting x=0 gives us 21(0) - y = 23. Simplifying, we have -y = 23. To isolate y, we can multiply both sides of the equation by -1, giving us y = -23.
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