Olivia Billbrough
Let's begin.

Cross Multiplication is a way of finding out a missing or simplify a number(s) by using 2 fractions. They are set equal to each other and then you cross multiply.

Example:

Cross_Mulitplying.png
because they are similar triangles they can be set equal to each other:
3/5=8/z
3z=40
z=13.3




EF-18
Sophia Moreno: 14

EF-18.png

Y = 3X + 15
Y = 3 - 3X

3X + 15 = Y = 3 - 3X
3X + 15 = 3 - 3X
6X + 15 = 3


X = -2

Y = 3X + 15
Y = 3(-2) + 15
Y = -6 + 15
Y = 9

(-2,9)