Find the non permissible replacement for a in this expression y-3/y+7

first 3plus 7 =10 then 10 y is your answer

now you help me

Alexandra makes a pattern she uses 2 square for every 3 triangles  in the pattern , how many triangles  will Alexandra uses if the pattern has 18 square?

in the attachment.   i didn't see your choices.   the word which means there is choices.

step-by-step explanation:

(x,y)

x tells you how much left or right you go from the origin

y tells you how much down or up you go from the origin

so for example (-3,2), you go left 3 and up twice. i denoted which of the ordered pairs is which in my graph.

the first one is x^2+2x+2

the second one is x^2+4

the last one is x^2-4x+8