Question 574159
{{{sqrt(x+1)=4}}}
{{{(sqrt(x+1))^2=(4)^2}}}
{{{x+1=16}}}
{{{x=16-1}}}
{{{x=15}}}



Check
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{{{sqrt(x+1)=4}}}
Put x=15
{{{sqrt(15+1)=4}}}
{{{sqrt(16)=4}}}
{{{sqrt((4)(4))=4}}}
{{{4=4}}}