Question 771442
Let the age of father to be x while of son to be y.
{{{x=2y^2-3}}} --> Equation 1
{{{x-y=42}}}
{{{x=42+y}}} --> Equation 2 ... Substitute {{{x=42+y}}} into Equation 1.
{{{42+y=2y^2-3}}} 
{{{0=2y^2-y-3-42}}} 
{{{0=2y^2-y-45}}} 
{{{2y^2-y-45=0}}} 
{{{(2y+9)(y-5)=0}}} 
{{{y=-9/2}}} or {{{y=5}}}
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{{{y=-9/2}}} is not accepted as answer because the age of a person can't be in negative.
while
{{{y=5}}} is accepted as answer.
When {{{y=5}}}, ... Substitute {{{y=5}}} into Equation 2
{{{x=42+5}}}
{{{x=47}}}
Therefore, the age of father is 47 while of son is 5.