Question 695447
Cross Multiply
{{{7/10 = 3/(x+1)}}}
7(x+1) = 3(10) ==> distribute the 7
7x + 7 = 30
7x = 30 - 7
7x = 23
{{{highlight_green(x=23/7)}}}
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Distribute the 10 and the negative 
10a + 10 - 14a = 9 - 4a + 1
-4a + 10 = 10 - 4a
-4a + 4a = 10 - 10
0 = 0
a can be any real number
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