Respuesta :
System A has 2 real solutions, System B has 0 real solutions and System C has 1 real solution.
Given a system of equations for A is x²+y²=17 and y=-(1÷2)x, a system of equations for B is y=x²-7x10 and y=-6x+5 and a system of equations for C is y=-2x²+9 and 8x-y=-17.
For system A,
The two systems of equations are
x²+y²=17 ......(1)
y=-1÷2x ......(2)
Substitute the value of equation (2) into equation (1) as
x²+(-x÷2)²=17
x²+(x²÷4)=17
Simplify the above equation by taking L.C.M. as
(4x²+x²)÷4=17
5x²=68
x²=68÷5
x=±3.688
Find the value of y by substituting the value of x in equation (2).
When x=3.688 then y is
y=-(1÷2)×3.688
y=-1.844
And When x=-3.688 then y is
y=-(1÷2)×(-3.688)
y=1.844
Thus, the points where the equations of system A intersect each other is (3.688,-1.844) and (-3.688,1.844)
So, the system of equations of A has 2 real solutions.
For system B,
The two systems of equations are
y=x²-7x+10 ......(3)
y=-6x+5 ......(4)
Substitute the value of equation (4) into equation (3) as
-6x+5=x²-7x+10
x²-7x+10+6x-5=0
x²-x+5=0
Simplify the above quadratic equation using the discriminant rule,
x=(-b±√(b²-4ac))÷(2a)
Here, a=1, b=-1 and c=5
Substitute the values in the discriminant rule as
x=(1±√(1-4\times 5\times 1))÷2
x=(1±√(-19))÷2
x=(1±√(19)i)÷2
Here, the value of x goes into the complex.
So, the system of equations of B has 0 real solutions.
For system C,
The two systems of equations are
y=-2x²+9 ......(5)
8x-y=-17 ......(6)
Substitute the value of equation (6) into equation (5) as
8x-(-2x²+9)=-17
8x+2x²-9+17=0
2x²+8x+8=0
Simplify the above quadratic equation using factorization method as
2x²+4x+4x+8=0
2x(x+2)+4(x+2)=0
(2x+4)(x+2)=0
x=-2,-2
Find the value of y by substituting the value of x in equation (5).
When x=-2 then y is
y=-2(-2)²+9
y=-8+9
y=1
Thus, the point where the equations of system C intersect each other is (-2,1)
So, the system of equations of C has 1 real solutions.
Hence, the system of equations for A is x²+y²=17 and y=-(1÷2)x having 2 real solution, a system of equations for B is y=x²-7x10 and y=-6x+5 having 0 real solution and a system of equations for C is y=-2x²+9 and 8x-y=-17 having 1 real solution.
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