In the figure above AB = 4x + 6 and BC = 7x + 15. If AC = 120, find the length of segment AB.

x = 9

Step-by-step explanation:

AB = 4x + 6 and BC = 7x + 15  AC is the sum of AB and BC

so 4x + 6 + 7x + 15 = 120 add like terms

11x + 21 = 120 subtract 21 from both sides

11x = 99 divide both sides by 11

x = 9

answer:

it is general formula that is used to write value to its excet position

a11 a12 a13

a21 a22 a23

it is the example of order 2 by 3 matrix in this

a11 means value occur in 1 st row 1st column

a12 means value occurs in 1st row 2nd column

a13 means value occur in 1st row and 3rd column

a21 means value occurs in 2nd row and 1st column

a22 means value occurs in 2nd row and in 2nd column

a23 means value occurs in 2nd row and in 3rd column

it would open into a square depending on the type of envelope i’m not sure about the second part