Answer:
This is a rectangle
Step-by-step explanation:
2D shape with 4 right angles would be a rectangle because 2 sides are equal and the other 2 would be equal to give you 4 right angles
X=2y
2x+5y=9
substitute the x=2y into the second equation
2(2y)+5y=9
multiple the 2y by 2. 4y+5y=9
combine like terms. 9y=9
divide the 9 out from both sides. y=1
plug the y back into the first equation
x=2(1)
multiply. x=2
your answer is: x=2
y=1
It sounds like initially we have a total of 18*5 = 90. Then we are adding 5 + 4 +3 +2 +1 to this.
so that gives us 105.
105/5 = 21
Value of x will be 
.
Equation given in the question → 
To find the value of 'x' in terms of a and b, we will simplify the given equation,
Therefore, Values to filled → Blank 1 = 15
Blank 2 = (a - b)
Learn more,
brainly.com/question/14318220
