Question
Solve the system by the addition method
-10x^2 + 10y^2-320=0
30x^2 + 6y^2 - 336 = 0
-10x^2 + 10y^2-320=0
30x^2 + 6y^2 - 336 = 0
Answers
Reiny
multiply the first by 3
-30x^2 + 30y^2 = 960
30x^2 + 6y^2 = 336, add them
36y^2 = 1296
y^2 = 36
y =±6
plug y = 6 into one of the equations and find the x
do the same with y = -6
-30x^2 + 30y^2 = 960
30x^2 + 6y^2 = 336, add them
36y^2 = 1296
y^2 = 36
y =±6
plug y = 6 into one of the equations and find the x
do the same with y = -6