2x + y = 20
-5y = -6x + 12
To use the substitution method, first isolate one of the variables in one of the equations.
Isolate the "y" in the first equation (because it is the easiest to isolate), and substitute it into the second equation:
2x + y = 20 Subtract 2x on both sides
y = 20 - 2x
-5y = -6x + 12 (since y = 20 - 2x, you can substitute 20 - 2x into y)
-5(20 - 2x) = -6x + 12 Multiply -5 into (20 - 2x)
-100 + 10x = -6x +12 Add 100 on both sides
10x = -6x + 112 Add 6x on both sides
16x = 112 Divide 16 on both sides
x = 7
Now that you have found x, you can substitute 7 into x for one of the original equations:
2x + y = 20
2(7) + y = 20
14 + y = 20 Subtract 14 on both sides
y = 6
-5y = -6x + 12
-5y = -6(7) + 12
-5y = -42 + 12
-5y = -30 Divide -5 on both sides
y = 6
x = 7, y = 6
The answer to the question is false
3 RIGHT TRIANGLES
1 big right triangle is divided into 2 smaller ones. Medium
and small.
<span> a.How far is the spot on the beach from the parking lot? </span>
Medium triangle: long leg = 32 m ; short leg = x
Small triangle: long leg = x ; short leg = 18m
32/x = x/18
32*18 = x*x
576 = x²
√576 = √x²
24 = x
Parking lot to the beach is 24 meters.
<span>b. How far will he have to walk from the parking lot to get to the refreshment stand?</span>
Use Pythagorean theorem:
Medium triangle: long leg = 32 m ; short leg = 24 m ;
hypotenuse = ?
32²+ 24² = c²
1024 + 576 = c²
1600 = c²
√1600 = √c²
40 m = c
Parking lot to refreshment stand is 40 meters.
$25 times 0.65 = $16.25 & then you do $25 - $16.25 which equals $8.75. So you save $8.75 by buying the pants on sale.
