2<3 | *-2
if the sign it is not changed ⇒ -4 < -6 but it is false ( the negative number is bigger when the number after is smaller)
⇒the sign must be changed
- 4 > -6
but in equation the sign remain " ="
⇒ in equation the change does not happen
Ex 3=2+1 | -2
-3*(-2)= - 6 = -2*(2+1)= - 4 - 2 true
The answer to the question is
Answer:
Resulting equation is
Step-by-step explanation:
Isolate y in the first equation 
divide both sides by 3
Now we substitute this value of y into second equation
Hence the resulting equation is
Notice that question doesn't says to solve so there is no need to simplify or solve that equation further
27x^2-81x-9x+27 In this case, just in your mind multiply 27 (coefficient of x^2) by the constant value 27(the end value of the quadratic trinomial). Then find factors that give you the value -90 when you add and 729 (27*27) when you multiply.
Factorise the values
27x( x-3)-9(x-3)
Which will give you
(27x-9)(x-3)
Yes, because they have the same measurements. the lines show they are the same
