4. which of these are solutions to the following system of equations?
x - 2y = 7
13x + 7y = 8
a. (7,0)
b. (5, -1)
d. (-2,2)
c. (3, -2)

Step-by-step explanation:

We have to check each one answer in the following system:

x - 2y = 7

13x + 7y = 8

a. (7,0)

7 - 2.0 = 7 (it's true)

13.7 + 7. 0 = 8 (it's false)

It isn't a correct answer.

b. (5, -1)

5 - 2.(-1) = 7 (correct)

13.5 + 7 (-1) = 8 (wrong)

It isn't a correct answer.

c. (-2,2)

-2 - 2.2 = 7 (wrong)

d. (3, -2)

3 - 2. (-2) = 7 (correct)

13.(3) + 7.(-2) = 8 (wrong)

So, none of them is answer.

the answer would be 150 books

step-by-step explanation:

if you divide 300 by 2 you will get 150

the final amount you will pay is $68.04.

the tip is determined by the pre-tax amount, so we calculate the tip based on the original bill, not after we've added sales tax.

to find the tip:

we can divide 54.00 by 100 to get 1% of 54. then we multiply that by 18.

54 / 100 = .54

.54 x 18 = 9.72

tip = 9.72$

to find the tax:

we can divide 54.00 by 100 to get 1% of 54. then we can multiply that by 8 to get 8%.

54 / 100 = .54

.54 x 8 = 4.32

tax= 4.32

now we can add the tip and tax to the bill to get our total.

54 + 9.72 + 4.32 = 68.04

total: $68.04

step-by-step explanation: