GEOMETRY HELLP :)

Step-by-step explanation:

angle S+angle T+angle+angle R=180 degree(being sum of interior angle of a triangle)

4x^2-6x+40+18x+3+2x^2-7=180

6x^2+12x+36=180

6(x^2+2x+6)=180

x^2+2x+6=180/6

x^2+2x+6=30

x^2+2x=24

x(x+2)=24

x+2=24/x

x=24/x-2

x=24-2x/x

substitute the value of x^2 in angle R

2x^2-7

2(24-2x/x)^2-7(here x and x gets cancel)

2(24-2)^2-7

2*22^2-7

2*484-7

968-7

961

it is a. 4.2 because 7.6-3.4 gets the remaining length of 4.2. i might be wrong but i am pretty sure this is the answer.

answer4 to the second power is 16

and 4 to the third power is 64,