In each case, you can use the second equation to create an expression for y that will substitute into the first equation. Then you can write the result in standard form and use any of several means to find the number of solutions.
System A
x² + (-x/2)² = 17
x² = 17/(5/4) = 13.6
x = ±√13.6 . . . . 2 real solutions
System B
-6x +5 = x² -7x +10
x² -x +5 = 0
The discriminant is ...
D = (-1)²-4(1)(5) = -20 . . . . 0 real solutions
System C
y = 8x +17 = -2x² +9
2x² +8x +8 = 0
2(x+2)² = 0
x = -2 . . . . 1 real solution
Answer:
-5,-11
8,14
Step-by-step explanation:
Let 's say r the commun difference
1)
1,1+r,1+2r,1+3r=-17
1+3r=-17
3r=-18
r=-6
Sequence is 1,-5,-11,-17
2)
2,2+r,2+2r,2+3r=20
2+3r=20
3r=18
r=6
Sequence is 2,8,14,20
84/100 which would then be 42/50 which will then be 21/25
9514 1404 393
Answer:
a[n] = n^2 -3n -6
Step-by-step explanation:
First differences are ...
-8 -(-8) = 0
-6 -(-8) = 2
-2 -(-6) = 4
Second differences are ...
2 -0 = 2
4 -2 = 2
Constant second differences indicate a degree 2 (quadratic) sequence.
The general formulation can be written as ...
an = a1 +(n -1)(d1 +(n -2)/2(d2)) . . . . where a1 is the first term; d1 is the first first difference; d2 is the second difference
= -8 +(n -1)(0 +(n -2)/2(2)) = -8 +(n -1)(n -2)
an = n^2 -3n -6 . . . . . formula for the n-th term
