Solve the simultaneous equations x^2 +8y=20 and y=x+4

To begin you must substitute the value of y provided into the first equation. The would change the equation into the following form:x^2+8(x+4)=20. Now expand the bracket so that the equation becomes:x^2+8x+32=20.Now subtract 20 from both sides to form a quadratic equationx^2+8x+12=0.Factorise the equation into (x+6)(x+2)=0 As 6 and 2 multiply to make 12 and add together to make 8. You can find all the factor pairs of twelve and check them to see if the add to make 8 in an exam to make sure there are no other possible answers. Since one of the two brackets must be equal to 0 x must be either -6 or -2 for this question. Substitute one of the values of x into the second equation provided.y=-6+4=-2. Therefore when x=-6, y=-2Repeat with the other value of x.y=-2+4=2. Therefore when x=-2, y-=2. In an exam remember to show your working as even if you come to the wrong answer you may still score some method marks which may boost your overall grade.