Answer: 
Step-by-step explanation:
The area of a square is 
Substituting d for x, you get 1/2x^2
Hope this helps <3
He spends $750, and makes $3000
3000/650=0.22
The answer is 22%
0.5 times 100 = 50... 50 is your answer
Answer:
R = 6S/T
Step-by-step explanation:
R ∝ S/ T
》R = kS/ T
》k = RT/ S
If R = 8 when S = 4 and T = 3
then, k = (8 × 3)/ 4
k = 6
∴ R = (6 × S)/ T
1. since the equations equal each other
2x+19=x+7
-x -x
x+19=7
-19 -19
x= -12
sub into y= x+7
y= -12+7
y= -5
2. x+2y=-7
<span>x+y+23=0
i don't know what the second equation is equal to, i'll assume 0
2y=x-7
y=1/2x-7/2
sub this into x+y+23=0
x+1/2x-7/2+23=0
3/2x+39/2=0
-39/2 -39/2
3/2x= -39/2
x=-39/2 / 3/2
x= -13
sub into y=1/2x-7/2
y=1/2(-13)-7/2
y= -10
3. </span>x+5y=2
<span>x=-4y+5
</span>sub x=-4y+5 into x+5y=2
-4y+5+5y=2
y+5=2
-5 -5
y= -3
sub y =-3 into x =-4y+5
x=-4(-3)+5
x= 17
4. 3x+y=9
<span>y=-5x+9
</span>sub -5x+9 into 3x+y=9
3x+(-5x+9)=9
3x-5x+9=9
-2x+9=9
-9 -9
-2x=0
x=0
sub into y=-5x+9
y=-5(0)+9
y=9
