Answer:
B
Step-by-step explanation:
-2×4
=-8
a negative number multiplied by a positive number gives a negative number that is why it is -8 and not 8
Answer:
x= 9
y=-12.5
Step-by-step explanation:
3x+2y = 2×2
2x+2y =-7×3
6x+4y =4
- 6×+6y =-21
-2y =25
y=-12,5
2x+2(-12,5)= -7
2x+-25= -7
2x= -7+25
2x/2=18/2
x= 9
Answer: it will take her 58 minutes to walk one mile.
Step-by-step explanation:
She walks at a constant rate of 30 seconds per lap and it takes her 46 steps to walk one full lap. It means that she walks 46 steps in 30 seconds.
If each step is approximately 1 foot, it means that the number of feet that she walks in 30 seconds is 46 feet.
1 foot = 0.000189 miles
Therefore, 46 feet would be
46 × 0.00189 = 0.008694 miles
Therefore, if she she walks 0.008694 miles in 30 seconds,
The time it will take her to walk 1 mile would be
30/0.008694 = 3450.66 seconds
Converting to minutes, it becomes
3450.66/60 = 58 minutes
High school math tip: learn how to apply the ratios 1:1:√2 for the 45/45/90 right triangle and 1:√3:2 for the 30/60/90 triangle; these two triangles probably constitute 90% of the examples and problems you'll see.
He we have half a square, the 45/45/90 isosceles right triangle, sides in ratio 1:1:√2. We write that ratio for our sides and solve.
1:1:√2 = (3/2)√2 : y : x
Ratios are pretty much like fractions, and we can make fraction equations out of corresponding pairs:
1/1 = ( (3/2)√2 ) / y
y = (3/2)√2
1 /√2 = (3/2)√2 / x
x = (3/2)√2 × √2 = (3/2)(2) = 3
Answer: y = (3/2)√2, x = 3
It's not too hard to get fast at these and just say y=(3/2)√2 because it's an isosceles triangle and x = y×√2 = 3 for the hypotenise.
