You will notice that 48°, x, and x lie upon a straight line. The sum of those angles must then be equal to 180°. Which means:
48+x+x=180
48+2x=180
2x=132
x=66°
2(x-3)=7x-31
2x-6=7x-31
-7x -7x
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-5x-6=-31
+6 +6
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-5x=-25
Divide by -5
x=5
3x-2(x+5)=-3+18
15
3x-2(x+5)=15
3x-2x-10=15
x-10=15
+10 +10
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x=25
v=πr^2(r+7) in my opinion is the correct expression
Do Pemdas
P:Parenthesis
E:Exponent
M:Multiplication
D:Divide
A:Addition
S:Subtraction