Let c be a real number, and consider the system of quadratic equations
y = 6x2 - 9x + c,
y = 5x2 - 3x.
For which values of does this system have:
(a) Exactly one real solution (x,y)Solutions to the quadratics are pairs.
(b) More than one real solution?
(c) No real solutions?
Solutions to the quadratics are (x,y) pairs.
Hello ZBRS7311,This question is about system of two quadratic equations, and it asks about which values of c does this system have: 1-Exactly one real solution2-More than one real solution3- No real solutionsThe strategy is to make use of the discriminant of a quadratic equation. Namely the quantity: Δ=b2−4ac Where Δ is called the discriminantBut the problem is, which quadratic equation shall we apply this on? Well, the quadratic equation that satisifies both "constraints" I.e. the intersection of both equations, I.e. equate both equationsHence, setting both equations equal to each other, (eliminating y), yields:⟹6x2−9x+c=5x2−3x⟺x2−6x+c=0Notice: a=1,b=-6,c=cNow for part (a) of the question, to have one real solution, the discriminant must be equal to zero⟺(−6)2−4(1)(c)=0⟹c=9Thus, this is the value of c such that the system has exactly one pair of (x,y) I.e. one solutionNext, for part (b), we want the system to have multiple solutions, this will be satisifed if and only if the discriminant is greater than 0⟺(−6)2−4(1)(c)>0⟹36−4c>0⟹c<9Thus, whenever c<9, the system will have more than one real solutionFor the last part, (c), for the system to have no solutions, the discriminant must be less than zero(−6)2−4(1)(c)<0⟹36−4c<0⟹c>9Therefore, to have no real solutions, c>9I hope this helps, and do not hesitate to ask further questions.