If P^2-QR=10, Q^2+PR=10, R^2+PQ=10, and R not= Q , what is the value of P^2+Q^2+R^2?
a) 10
b) 15
c) 20
d) 25
e) 30
OA: C
step 1: Subtract equation 2 from equation 3
step 2: Sum all given equations
step 3: and apply the resultant of step 1 in step 2.
I understand this method. However, how will one know to solve it this way?... subtracting one equation from another, summing all equations and then applying the intermediate result to obtain final result.
What is the concept behind this? Please help.
a) 10
b) 15
c) 20
d) 25
e) 30
OA: C
step 1: Subtract equation 2 from equation 3
step 2: Sum all given equations
step 3: and apply the resultant of step 1 in step 2.
I understand this method. However, how will one know to solve it this way?... subtracting one equation from another, summing all equations and then applying the intermediate result to obtain final result.
What is the concept behind this? Please help.
