3x=1x+5
ummm are the red circles a plus or minus ??
To find the area of a circle, you do π × diameter (in this case 10). They have told you to use 3.142 as π, so you do 3.142 × 10 = 31.42. Because it's a semi-circle, you need to halve 31.42 to get 16.21, which is the answer
To find the area of an obtuse triangle you have to multiply the base of the triangle by the vertical height and divide the result by 2 following the formula:

The base of the triangle is b= 7 miles and the height is h= 8 miles, using these lengths calculate the area as follows:

The area of the triangle is 28 square miles.
If a plane flies an average of 325 miles per hour, to find out 7 hours you will need to times 325 by 7.
325 x 7 = 2275.
therefore the flight for 7 hours was 2275 miles.
(4a + 6b) x (2a - 2b)
the answer would be 8a2 + 4ab - 12b2