Explain a different method you could use to solve problem 11 ?

You want to get all of the equations into standard form:

ax+b

with a being the coefficient and b being the constant.

so the first one is correct

For equations 2 and 3 you want to make the denominators the same so that you can add them.

for (1/4)x and -(1/12)x you can make the denominator twelve and for the constants you can make the denominator 10.

for (1/18)x and (1/9)x you can make the denominator 18, and the constant is already there, no work needed

answer:  

step-by-step explanation:

here x represents the height of the pole,

and, the height of the shadow of the pole is 12 feet.

also, the angle of elevation from the top of the pole is 40°,

therefore,

by the low of sine,

which is the required equation for finding the value of x,