Brainliest goes to whoever answers correctly and explains also if you want extra points answer my other questions

1) y=-10x+50 (it's the only negative slope / going down option and it starts at x=0 y=50)

just substitute the x with a 9

y=-10*9 +50

y= -40

2) 0.5x +5 (only positive slop and starting point at x=0 is correctly 5)

we do need to substitute y this time, with 30 obviously

30 = 0.5x +5 |-5

25 = 0.5x | *2

50 = x

3) y=-2x +50 reasoning as before

substitute x with 4

y =-2*4 +50

y = -8 +50

y = 42

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