I think its not a correct solution of given equations.
Answer:
x = -2
y = 3
Step-by-step explanation:
from above equation we get ,
=》y = 3x + 9
now ,
by second equation,
=》2x + 3y = 5
=》2x + 3 × ( 3x + 9 ) = 5
( since, y = 3x + 9 , by equation 1 )
=》2x + 9x + 27 = 5
=》11x = -22
=》x = -2
putting value of x in equation 1 ;
=》 y = 3x + 9
=》 y = 3 × ( -2 ) + 9
=》 y = -6 + 9
=》 y = 3
Okay so the area of a rectangle x by y with a border of width b will be:
A=(x+2b)(y+2b)
A=xy+2bx+2by+4b^2 we are told that A=320, x=11, and y=15 so now we have:
320=165+22x+30x+4x^2, now I am using x as the border width...
4x^2+55x+165=320 is the equation that they listed..
...
4x^2+55x-155=0 using the quadratic formula for efficiency...
x=(-55±√5505)/8 since x>0
x≈2.399 which for some unknown (incorrect) reason they rounded to
x=2.5
So in short, your answer is a)
