what is the solution to the system of equations?

5x + 4y = 8
x - 2y = 10
(not multiple choice)
my answer: (-5, -1)

What are the missing values? (coincident)

4x + 5y = 8
8x + ____ y = _____
(Not multiple choice)
Im not sure how to do this one

collection of dimes and nickels is worth $6.90. but there are 96 coins all together.. how many coins are there?
______ (not multiple choice) not sure how to do it ..

______

-120

#1, you can decide for yourself if (-5,-1) is correct by subbing in those values into both equations.

You should be able to do this mentally.
-- A quick mental calculation shows that your answer does not work in either equation

from the 2nd: x = 2y + 10
plug that into the 1st:
5x + 4y = 8
5(2y+10) + 4y = 8
10y + 50 + 4y = 8
14y = -42
y = -3
then x = 2y+10 = -6+10
= 4
so x = 4, y = -3

2.
Since they are to be coincident, the 2nd equation should be equivalent to the 1st
since 4x was multiplied by 2 to get 8x in the 2nd
do that to the other two terms.

3. d+n = 96 --> n = 96-d

10d + 5n = 690
10d + 5(96-d) = 690

take it from there ....

–24 • 5 = ?

What is the product of –8 and –7?

The product of -8 and -7 is 56.

Which of the following has a product of –40?

A. (2)(20)
B. (–4)(–10)
C. (8)(–5)
D. (–7)(60)

Option C (8)(-5) has a product of -40.

Which integer represents the total change in altitude of an airplane descending 5 feet every second for 15 seconds?

A. 65
B. 75
C. –75
D. –65

The altitude of the plane is decreasing at a rate of 5 feet per second and it is descending for 15 seconds, therefore the total change in altitude can be found by multiplying 5 by 15 which gives us -75. So, the correct answer is C: -75.

10 • –5 • –4 • 3 = ?