Answer:
1) {y,x}={-3,-23}
2) {x,y}={7,-9/2}
Step-by-step explanation:
Required:
- Solve systems of equations
1) y - x = 20, 2x - 15y = -1
Equations Simplified or Rearranged :
[1] y - x = 20
[2] -15y + 2x = -1
Graphic Representation of the Equations :
x + y = 20 2x - 15y = -1
Solve by Substitution :
// Solve equation [1] for the variable y
[1] y = x + 20
// Plug this in for variable y in equation [2]
[2] -15•(x +20) + 2x = -1
[2] - 13x = 299
// Solve equation [2] for the variable x
[2] 13x = - 299
[2] x = - 23
// By now we know this much :
y = x+20
x = -23
// Use the x value to solve for y
y = (-23)+20 = -3
Solution :
{y,x} = {-3,-23}
2) 25-x=-4y,3x-2y=30
Equations Simplified or Rearranged :
[1] -x + 4y = -25
[2] 3x - 2y = 30
Graphic Representation of the Equations :
4y - x = -25 -2y + 3x = 30
Solve by Substitution :
// Solve equation [1] for the variable x
[1] x = 4y + 25
// Plug this in for variable x in equation [2]
[2] 3•(4y+25) - 2y = 30
[2] 10y = -45
// Solve equation [2] for the variable y
[2] 10y = - 45
[2] y = - 9/2
// By now we know this much :
x = 4y+25
y = -9/2
// Use the y value to solve for x
x = 4(-9/2)+25 = 7
Solution :
{x,y} = {7,-9/2}
Answer: on the number line put -1.50 (1 and a half (1 1/2))
Step-by-step explanation:
$1.50 more than his account is $200.
the balance should be $-1.50
on the number line put -1.50
Answer:
1269 square meters
Step-by-step explanation:
The path and the plot of land form two concentric circles (they have the same center). The radius of the plot of land is 100m (half of the diameter) and the radius of the larger circle, formed by putting a 2m wide path around the plot of land, is 102m. Thus, the area of the path is
minus
which will be
which is
. Estimate
to 3.141 and calculate, getting 1268.964... which is 1269, rounded to the nearest square meter.
Hope this helps :)
Answer:
its 130
Step-by-step explanation: