Solve the simultaneous equations: (1) y – 2x – 4 = 0 , (2) 4x^2 + y^2 + 20x = 0
Rearrange (1): y=2x+4
Subsitute this into (2): 4x2+(2x+4)2+20x=0
Simplify and collect like terms: 8x2+36x+16=0
Factorise: (2x+1)(x+4)=0
Therefore: 2x+1=0 -> x=-0.5 and x+4=0 -> x=-4
Substitute this into (1) to get values for y: y=3 and y=-4
AT
