Answer:
25
Step-by-step explanation:
2x+2+5x+3=180 (angles on a straight line)
7x+5=180
7x=180-5
7x=175
x=25 (dividing both sides by 7)
I would use the quadratic formula for this:
x = -b ± √b² - 4ac over 2a
x = 8 ± √64 - 4(1)(0) over 2(1)
x = 8 ± √64 over 2
x = 8 <span>± 8 over 2 [simplify]
x = 4 </span><span>± 4
x1 = 4 + 4 x2 = 4 - 4
x1 = 8 x2 = 0
Thus, the solutions for x would be 0 and 8.</span>
Answer:11
Step-by-step explanation:
Boys : girls=7:1
Sum of ratio=7+1=8
Let them number of girls be y
Then they number of boys=y+66
Total number of pupils=y+y+66
Total number of pupils=2y+66
Number of girls=(girls ratio)/(sum of ratio) x (total number of pupils)
y=1/8 x (2y+66)
Cross multiply
y x 8=2y + 66
8y=2y + 66
Collect like terms
8y-2y=66
6y=66
Divide both sides by 6
6y/6=66/6
y=11
The number of girls is 11
So to solve for x, you'll need to combine all the angles and equal it to 720, and from there we can solve.

Combine like terms to get

Subtract 470 on each side to get

Then just divide on each side and you'll get

To find the value of the (x+10) angle, just substitute 125 for x and solve.