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
first：76 ÷ 19/25=100
a:80 / 20 * 1 / 25 =0.16
b:80 * 5/4 =100
c:80 / 5 ÷ 1 / 4 =64
d:80 * 5/4 =100
e:80 * 4/5 =64
So I think both B and D should be the right answer
(3 * 10,000) + ( 9* 1,000) + ( 5* 1)
It will takes Horst 12 minutes to run 15 laps
