18- 5x
19- 6x
I'm not sure but I had a test like this
Total bill-$67.95
each friends owes about $16.99
5x+2y >/= 5
*>/= : it's the greater than or equal sign
Hello,
Answer C : always Al Kashi
<u>Answers</u>
1. (3 + xz)(–3 + xz)
2. (y² – xy)(y² + xy)
3. (64y2 + x2)(–x2 + 64y2)
<u>Explanation</u>
The difference of 2 squares is in the form (a+b)(a-c).
<span>(3 + xz)(–3 + xz) = (3 + xz)(xz -3)
= (xz + 3)(xz - 3)
= x</span>²y²-3xy+3xy-9
<span> =x</span>²y² - 3²<span>
(y</span>² – xy)(y² + xy) = y⁴+xy³-xy³-x²y²
<span> = y</span>⁴ - x²y²
<span>
(64y2 + x2)(–x2 + 64y2)= (64y</span>²+x²)(64y²-x²)
= 4096y⁴-64y²x²+64y²x²-x⁴
= 4096y⁴ - x⁴
