Step-by-step explanation:
-9x-4y=1....eq1
3x+3y=3.....eq2
multiply eq2 by 3
to get
9x+9y=9....eq3
add eq1 and 3
0+5y=10
5y=10
divide both sides by 5
y=2
substitute y=2 in to eq1
-9x-4(2)=1
-9x-8=1
grouping of like terms
-9x=1+8
-9x=9
divide both sides by -9
x= -1
now the answer is
x= -1, y=2
Solution would be: a value or values that make a mathematical sentence true.
Answer:

Step-by-step explanation:
To solve, first subtract 2x from both sides.

You appear to want the solution for -y, so I've included it. Given that you also want the solution for y, divide both sides by -1.

It is false. It can be proven with a counterexample. The counterexample may be a rhombus. Rhombus is a quadrilateral, is not a rectangle and its diagonal bisect each other.