Answer: 
Step-by-step explanation:
multiply everything by -7
Answer:
x= -3
Step-by-step explanation:
mutliply the -3 to parentheses.
-3x+12 = 21
-3x = 21-12
/-3
x= 9/-3
x= -3
Well it's 33. The 5 step problem thing I'm not to sure of.
Answer:
√135
Step-by-step explanation:
3^2+b^2=12^2
9+b^2=144
9-9+b^2=144-9
b^2=135
√135=b
<span>4x+2y=10
x-y=13
x=13+y
4(13+y)+2y=10
52+4y+2y=10
52+6y=10
6y=-42
y=-7
x=13+y=13-7=6
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