Answer:
(64,86.5)
Step-by-step explanation:
find the case where he gets 70 and the case where he gets 79
if his average is 70:
(75+62+85+2x)/5=70
(222+2x)/5=70
222+2x=350
2x=128
x=64
if his average is 79:
(75+62+85+2x)/5=79
(222+2x)/5=79
222+2x=395
222+2x=395
2x=173
x=86.5
Replace the x with 2: f(2)=2*2+7=4+7=11
replace the x with 7: f(7)=2*7+7=14+7=21
An isosceles triangle. This triangle has 2 sides that are equal.