4bags of cement do 18m2, how many m2 can be done with 7 bags?

You would get 31.5 square meters.

Step-by-step explanation:

To find this, set up a proportion of the amount the first can make and the amount the second can. Use x for the unknown quantity.

4/18 = 7/x

Now cross multiply to solve.

7*18 = 4*x

126 = 4x

31.5 = x

b

step-by-step explanation:

the equation of a line in point- slope form is

y - b = m(x - a)

where m is the slope and (a, b) a point on the line

calculate m using the slope formula

m = (y₂ - y₁ ) / (x₂ - x₁ )

with (x₁, y₁ ) = (0, 4) and (x₂, y₂ ) = (3, - 5) ← 2 points on the line

m = = = - 3

with m = - 3 and (a, b) = (3, - 5), then

y - (- 5) = - 3(x - 3), that is

y + 5 = - 3(x - 3) → b