Answer:
x = 1, y = -2
Step-by-step explanation:
15x + 3y = 9 (1)
10x + 7y = -4 (2)
3 × (2) - 2 × (1)
3 × (2)
30x + 21y = -12 (3)
2 × (1)
30x + 6y = 18 (4)
(3) - (4)
15y = -30
y = -30 / 15
y = -2
sub y = -2 into (1)
15x + 3y = 9
15x + (3 × -2) = 9
15x - 6 = 9
15x = 9 + 6
15x = 15
x = 15 / 15
x = 1
Answer: B) 0 real roots
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The general rule is...
if D > 0, then you have two different real roots (see note below)
If D = 0, then you have exactly one real root
If D < 0, then you have no real roots (the two roots are imaginary/complex)
where D is the discriminant found by the formula
D = b^2 - 4ac
Note: If D is also a perfect square, then the two real roots are also rational. This assuming that a,b,c are rational.
Answer:
c and a
Step-by-step explanation:
All birds, but penguins can fly
