Respuesta :
so what you do is solve for y in 2nd equation
minus 2x boh sides
y=-2x-5
sub that for y in other equation
x^2+(-2x-5)^2=25
x^2+4x^2+20x+25=25
5x^2+20x+25=25
mminus 25 both sides
5x^2+20x=0
factor
(x)(5x+20)=0
set to zero
x=0
5x+20=0
5x=-20
x=-4
sub back
y=-2x-5
y=-2(0)-5
y=-5
a point is (0,-5)
y=-2x-5
y=-2(-4)-5
y=-8-5
y=-13
another is (-4,-13)
(0,-5) and (-4,13)
I think it is C, but you forgot to put that 1 infront of the 3
minus 2x boh sides
y=-2x-5
sub that for y in other equation
x^2+(-2x-5)^2=25
x^2+4x^2+20x+25=25
5x^2+20x+25=25
mminus 25 both sides
5x^2+20x=0
factor
(x)(5x+20)=0
set to zero
x=0
5x+20=0
5x=-20
x=-4
sub back
y=-2x-5
y=-2(0)-5
y=-5
a point is (0,-5)
y=-2x-5
y=-2(-4)-5
y=-8-5
y=-13
another is (-4,-13)
(0,-5) and (-4,13)
I think it is C, but you forgot to put that 1 infront of the 3
Answer:
Option C is correct
the solution for the given system of equation is, (0, -5) and (-4, 3)
Step-by-step explanation:
Using identity:
[tex](a+b)^2=a^2+b^2+2ab[/tex]
Given the equation:
[tex]x^2+y^2=25[/tex] .....[1]
[tex]2x+y=-5[/tex] .....[2]
We can write [2] as:
[tex]y = -5-2x[/tex]
Substitute this in [1] we have;
[tex]x^2+(-5-2x)^2=25[/tex]
Using identity rule;
[tex]x^2+25+4x^2+20x = 25[/tex]
Combine like terms;
[tex]5x^2+20x+25 = 25[/tex]
Subtract 25 from both sides we have;
[tex]5x^2+20x=0[/tex]
⇒[tex]5x(x+4)=0[/tex]
By zero product property we have;
x = 0 and x+4 = 0
x = 0 and x = -4
Substitute these in [2] we have;
for x = 0
2(0)+y = -5
⇒[tex]y = -5[/tex]
For x = -4 ,
[tex]2(-4)+y = -5[/tex]
-8+y = -5
add 8 to both sides we have;
y = 3
Therefore, the solution for the given system of equation is, (0, -5) and (-4, 3)