Answer:
D.5
Step-by-step explanation:
You can write the following equations from the information given:
y=x+3 (1)
11x+5y=47 (2)
x is the number of hardback books
y is the number of paperback books
You can replace (1) in (2):
11x+5(x+3)=47
11x+5x+15=47
16x=47-15
16x=32
x=32/16
x=2
Then, you can replace the value of x in (1) to find the value of y:
y=2+3
y=5
According to this, the answer is that Jamal bought 5 paperback books.
Ok so cos(x) = sin(90-x) so using that you can get sin(7x-15) = sin(90-(3x+5)) so 7x-15 = -3x+85. 10x = 100 and x = 10. Use that to find the 2 angles are 55 and 35
