<span>(4 х+1)</span>²<span>-(4х+3)(4х-3) = 6x-2
16x</span>²+8x+1-(16x²-9)=5x-2
16x²+8x+1-16x²+9=6x-2
8x+10=6x-2
8x-6x=-2-10
2x=-12
x=-12:2
x=-6
Sorry, I don't know. Please translate this and send to me.
<span>а7=98 а14=42
a7 = a1 + 6b
a14 = a1 13b
a1+6b -98 = 0
a1 +13b -42 = 0
</span>
a1+6b -98 = <span>a1 +13b -42
</span>
6b -98 = <span>13b -42
-98 +42 = 13b - 6b
7b = -56
b = -8
a7 = a1 +6b
98 = a1 -6*8
a1 = 98 +48
a1 = 146
</span>
<span>а6+а14=30
a14 = 30 - a6
a1 +13b = 30 -a1 -5b
2a1 +18b = 30
a1 + 9b = 15
a10 = 15
</span>
B₁ + b₁ q + b₁ q² = 78/125
b₁ (1 + q + q² )= 78/125 |q| < 1
S = b₁/(1-q)
b₁ = S/(1 - q) = 2/3(1 - q)
2/3(1-q)(1+q+q²) = 78/125
1 - q³ = 78/125 : 2/3
1 - q³ = 117/125
q³ = 1 - 117/125 = 8/125
q = ∛8/125 = 2/5
b₁ = S * (1 - q) = 2/3 * (1 - 2/5) = 2/3 * 3/5 = 2/5 = 0,4
(6-x)(6+x)+10x²<(3x+1)²
36-x²+10x²<9x²+6x+1
35+9x²<9x²+6x
6x>35
x>35/6
x>5⁵/₆.