Solve the system of linear equations using elimination.
10x + 10y = −10
9x + 10y = −18
a) (8, 9)
b) (8, −9)
c) (−8, 9)
d) (−8, −9)

(x , y) = (8, -9)

Step-by-step explanation:

We have the equations as,

10x + 10y = -10 (1)

and

9x + 10y = -18 (2)

Now deducting (2) from (1) we get,

x = 8 (3)

Putting the value of x from (3) in (1) we get,

10y = -90

⇒y = -9 (4)

So, from (3) and (4) we get that,

(x , y) = (8, -9)  (Answer)

1     3    

step-by-step explanation:

hopefully im right

hello,

b) 62.47% of the students are between 14 and 18 years old.

step-by-step explanation:

mean = 15 and standard deviation = 2

student between 14 to 18

formula used z-score

for age 14 , z score

using z-table , p(z> -0.5)=0.3085

for age 18 , z score

using z-table , p(z< 1.5)=0.9332

p(-0.5< z< 1.5)=0.9332-0.3085 = 0.6247

thus, 62.47% of the students are between 14 and 18 years old.

click to let others know, how is it

0.0

0 votes

1

report

read more on -

step-by-step explanation: