y = −2x + 13
y = 2x − 3
Set the equations to equal and solve for x:
-2x + 13 = 2x -3
Add 2X to each side:
13 = 4x -3
Add 3 to each side:
16 = 4x
Divide both sides by 4:
x = 16/4
x = 4
Now replace x with 4 in one of the equations and solve for y:
y = -2(4) +13
y = -8 +13
y = 5
x = 4 and y = 5 , which is the ordered pair (4,5)
Both numbers are positive values, so the second graph is correct.
If the dots are going to the right, it's positive. If they're going to the left, they're negative.
Answer:
12 boys
Step-by-step explanation:
From the above question:
Number of boys = 3
Number of girls = 2
Boys: Girls
3:2
Let :
a = boys
b = girls
Hence, a : b = 3 : 2
a/b = 3/2
Cross Multiply
2a = 3b .......... Equation 1
a = 3b/2
If four more girls join the class, there will be the same number of boys and girls
Hence,
a: b + 4 = 3 : 3
a/b + 4 = 3/3
Cross Multiply
3a = 3(b + 4)
3a = 3b + 12 ........ Equation (2)
From Equation 1: a = 3b/2
Substitute 3b/2 for a in Equation 2 we have:
3a = 3b + 12 .........Equation 2
3(3b/2) = 3b + 12
9b/2 = 3b + 12
Cross Multiply
9b = 2(3b + 12)
9b= 6b + 24
9b - 6b = 24
3b = 24
b = 8
Substitute 8 for b in Equation 1
a = 3b/2
a = 3 × 8/2
a = 24/2
a = 12
Therefore, the number of boys in the class is 12
