Answer:
Step-by-step explanation:
move all the terms to the right so your equation will equal 0. then look for the common denominator. which in this case is 60 (5*4*3).
multiply all terms by 60 then simplify.
12(2x-3)-15(6-3x)+120-20(7x)=0
24x-36-90+45x+120-140x=0
combine like terms and then divide
-71x=6
x=-6/71
(do not forget parenthesis when simplifying they are very important when it comes to distributing the minus sign)
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:
A=30cm, B=39cm
Step-by-step explanation:
They are an enlargement. Therefore, the sides are larger by the same proportion, otherwise, it wouldn't be an enlargement. Therefore, the bottom side of the big one is 3 times that of the small one. Therefore, the other sides are also 3 times, making A = 30cm and B = 39cm.
F=9/5C+32
rewrite as 9/5C+32=F
9/5C+32-32=F-32
9/5C=F-32
(5*9/5)C=(F-32)*5
9C=5F-160
9/9C=(5F-160)/9
C=(5F-160)/9