Answer: 
<u>Step-by-step explanation:</u>
EQ1: x + y = 12 --> x = 12 - y
EQ2: xy = 15
Substitute x = 12-y into EQ2 to solve for y:
(12 - y)y = 15
12y - y² = 15
0 = y² - 12y + 15
↓ ↓ ↓
a=1 b= -12 c=15

Now, let's solve for x:

Lastly, find x² + y² :



Answer:
28meters and 112meters
Step-by-step explanation:
one piece is x
the other is 4x
therefore; 4x+x=140
5x= 140
divide both sides by 5
x=28
4x=4(28)
=112
Answer:
x=6
Step-by-step explanation:
x+3=9
x+3-3=9-3
x=6
Answer:
No solution
Step-by-step explanation:
3x + 6y =36
-3x - 6y =0
------------------add
0 ≠ 36
No solution
X = nr. hrs working for a farmer;
y = nr. hrs. babysitting;
x + y <= 25;
10x + 5y >= 150
a) Solve the system => one of the solution is x =5; y = 20(babysitting)
b) 10 + 12 =22 <= 25; 10*10 + 5*12 = 160 >=150.