Answer:
17
Step-by-step explanation:
AB + BC = AC.
Therefore,
[tex](3x+2)+(5x+7)=49[/tex]
Remove brackets:
[tex]3x+2+5x+7=49[/tex]
Add up terms:
[tex]8x+9=49[/tex]
Subtract 9 from both sides:
[tex]8x+9-9=49-9[/tex]
[tex]8x=40[/tex]
Divide both sides by 8:
[tex]\frac{8x}{8}=\frac{40}{8}[/tex]
[tex]x=5[/tex]
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[tex]AB=3x+2=3(5)+2=15+2=17[/tex]
