Solve algebraically the simultaneous equations 2x^2-y^2=17 and x+2y=1
To solve these equations, we have to rearrange the second equation to make x ‘the subject’ and then we can substitute it into the first one. First, subtract 2y from both sides so x=1-2yNext substitute this into the first equation, so 2(1-2y)2-y2=17Now expand the brackets. 2-8y+8y2-y2=17rearrange to form a quadratic equation: 7y2-8y-15=0now, factorise this: (7y-15)(y+1)=0this can be solved by considering y+1=0 and 7y-15=0, giving the solutions y=-1 and y=15/7when y=-1, x=1+2=3when y=15/7, x=1-30/7=-23/7
BH
Related Maths GCSE answers
All answers ▸What is the cosine rule?
ABC is a right angled triangle. D is the point on AB such that AD = 3DB. AC = 2DB and angle A = 90 degrees. Show that sinC = k/√20 where k is an integer. Find the value of k
The straight line L1 passes through the points with coordinates (4, 6) and (12, 2) . The straight line L2 passes through the origin and has a gradient of -3. The lines L1 and L2 intersect at point P. Find the coordinates of P.
Solve the simultaneous equations 2x + y = 7 and 3x - y = 8