The equation of a line which has the slope m and passes through the point A(x1,y1) has the formula:
y-y1=m(x-x1)
in your case m= -5 ; A(x1;y1)=(1;-1)
y-(-1)= -5(x-1)
y+1= -5(x-1)
answer is c
Solve simultaneously.
4x - y = 8
6x + y = 2
Multiply top equation by 6, and bottom equation by 4, to eliminate x, so that we can find y.
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24x - 6y = 48
24x - 4y = 8
Subtract top from bottom to form one equation.
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-2y = 40
Therefore y is 20.
Put y back in to an equation, such as 4x - y = 8.
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4x - 20 = 8
4x = 28
x = 7
The answer is A. for this, you have to set up a system of equations. the first one will be the area equation. since you know area=length x width, your equation will be LxW=50. the next equation is L=2W, since the length is two times the width. then, plug in 2W for the L in the other equation and you get 2W^2=50. divide by 2 and get W^2=25. square root both sides and you get W=5. plug back into the other equation to find L=10. Then, add the sides of the rectangle for the perimeter. 10+5+10+5=30.
