p²-q²
p²-q²= (p+q)(p-q)
[by formula: (A+B)(A-B) = A²-B²]
<em>Proof of the formula</em>
<em>Proof of the formula (A+B) • (A-B) </em>
<em>Proof of the formula (A+B) • (A-B) = A2 - AB + BA - B2 </em>
<em>Proof of the formula (A+B) • (A-B) = A2 - AB + BA - B2 = A2 - AB + AB - B2 </em>
<em>Proof of the formula (A+B) • (A-B) = A2 - AB + BA - B2 = A2 - AB + AB - B2 = A2 - B2</em>
D=2n
.05n+.1d=3.5
I multiplied the nickels and dimes by these values because that is their actual monetary value
.05n=3.5-.1d
multiply everything by 20
n=70-2d
d/2=70-2d
.5d+2d=70
2.5d=70
d=28
n=14
so there are <u>28 dimes and 14 nickels
</u>checking this answer
28 dimes = $2.8
14 nickels = .70
2.8+.7=3.5
Answer:
solution for -4 + 3y = 23
3y = 23+4
3y = 27
y = 9
solution for X - y = -7
X = 1
y = 8