Question

Solve algebraically the simultaneous equations

x^2 + y^2 = 25
y = 2x - 2

Give your final pairs of values in the form,
x = ....., y = ....., and x = ....., y = ..... ​

Answer 1

x^2 + ( 2x-2 )^2 = 25
x^2 + 4x^ - 8x + 4 = 25
5x^2 - 8x - 21 = 0
( x - 3 ) ( 5x + 7 ) = 0

so x = 3 , or x = -7/5 -14/5 - 10/5= -24/5
( -&- = + )

Ans:
x = 3 , x = -7/5 and y = 4 , y = -24/5