grade ten math

[jodiiss]

determin weather the equations are equivilent:

a) y=2(x-3)�
y=2x�-12x+11

b) y=(x-5)�-25
y=x�-10x

[lycosa]

a) y=2(x-3)�
y=2x�-12x+11

(x-3)� = (x-3)(x-3) = x� -6x+9
so 2(x-3)� = 2(x� -6x+9) = 2x�-12x+18

2x�-12x+11 isn't same as 2x�-12x+18, therefore equations aren't equivalent

b) y=(x-5)�-25
y=x�-10x

(x-5)� = (x-5)(x-5) = x�-10x+25
so (x-5)�-25 = x�-10x+25-25 = x�-10x, therefore equations are equivalent