OG详解-OG6 数学1 Q20

The correct answer is 1895​​. A y-intercept of a graph in the xy-plane is a point where the graph intersects the y-axis, which is a point with an x-coordinate of 0. Substituting 0 for x in the given equation yields  3(0)7​=5y9​+21​, or 0 = - 5y​9​+21. Subtracting 21 from both sides of this equation yields -21 = -5​y9​. Multiplying both sides of this equation by -9 yields 189 = 5y. Dividing both sides of this equation by 5 yields 1895​​ = y. Therefore, the y-coordinate of the y-intercept of the graph of the given equation in the xy-plane is189​5​ . Note that 189/5 and 37.8 are examples of ways to enter a correct answer.