QUADRATIC EQUATION – WORD PROBLEMS Fatima got 16 marks more than Zahra in Math test. The product of their mark is 1380. Find their marks.

The answer 30 ,46
I just need the steps

Fatima's points = 46

Zahra's points = 30

Step-by-step explanation:

Let's give names to the unknowns (the number of points each one got)

Fatima's points = y

Zahra's points = x

Now create the equations given by the info they provide:

"Fatima got 16 marks more than Zahra"

y = x + 16

"The product of their mark is 1380."

x * y = 1380

Now use the first equation as substitution for "y" in the second equation:

x * (x + 16) = 1380

reduce the expression:

x^2 + 16 x = 1380

x^2 + 16 x - 1380= 0

Solve using quadratic formula:

we pick 30 since the scores from a test must be larger than zero.

Now we use the first equation to solve for the other variable;

y = 30 + 16 = 46

then x = 30 and y = 46

a) 40 more; b) old factory:   10%, new factory:   16%; c) week 4

explanation:

a) at week 0, we see in the graph that the new factory produces 190 specialty items.  

using the function, substituting 0 in for w,

this is a difference of 230-190 = 40.

b) the function for the old factory is written in the form f(x) = a(1+r)ˣ, where a is the original amount, x is the amount of time and r is the growth rate.   the equation for the old factory is ; 230 is in place of a and is the original amount; w is the amount of time; which means 1+r = 1.1.   this means that r must be 0.1 or 10%.

for the new factory, we find the percent of increase to find the growth rate; the formula for this is

between the first two points, the amount of change is 220-190 = 30; this gives us

30/190 = 0.158 ≈ 0.16 = 16%

c) at week 0, the old factory has 230 while the new factory has 190.

at week 1, the old factory has 230(1.1) = 253 while the new factory has 220.

at week 2, the old factory has 230(1.1²) = 278.3 while the new factory has 252.

at week 3, the old factory has 230(1.1³) = 306.13 while the new factory has 290.

at week 4, the old factory has 230(1.1⁴) = 336.743 while the new factory has 337.   this is the first week that the new factory surpasses the old.

given the equation is 8+9z=-6, the first step would be to subtract the 8 from both sides:

8+9z-8=-6-8

since 8 minus 8 = 0, this would cancel out the 8. and since -6 minus 8 equals -14, the equation would look like this

9z = -14