Answer:
b = 43
Explanation:
So let's plug things in first:
y= 2x - 20 and y= -5x +b which can become →
2x - 20 = -5x + b (now you said that x=9 so let's plug that in)
2(9) -20 = -5(9) + b (now try solving that)
18 -20 = -45 + b → -2 = -45 + b ( so then add 45 to both sides)
43 = b ( and there's your answer )